diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/axisFactory.ts b/packages/perspective-viewer-d3fc/src/ts/axis/axisFactory.ts
index e8a7484cae..a75d3cab2a 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/axisFactory.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/axisFactory.ts
@@ -22,7 +22,6 @@ import {
     D3Scale,
     Domain,
     DomainTuple,
-    GetSetReturn,
     Orientation,
     SettingNameValues,
     Settings,
@@ -50,30 +49,29 @@ export interface AxisFactoryContent {
 
 interface AxisFactory {
     (data: any[]): any;
-    memoValue: <T extends Axis | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Axis, AxisFactory>;
-    excludeType: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, AxisFactory>;
-    orient: <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Orientation, AxisFactory>;
-    settingName: <T extends SettingNameValues | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, SettingNameValues, AxisFactory>;
-    settingValue: <T extends string | null | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string | null, AxisFactory>;
-    valueName: <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName, AxisFactory>;
-    valueNames: <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName[], AxisFactory>;
-    modifyDomain: <T extends ModifyDomainFunc | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ModifyDomainFunc, AxisFactory>;
+    memoValue(): Axis;
+    memoValue(a: Axis): AxisFactory;
+
+    excludeType(): () => AxisTypeValues;
+    excludeType(nextExcludeType?: AxisTypeValues): this;
+
+    orient(): () => Orientation;
+    orient(nextOrient?: Orientation): this;
+
+    settingName(): () => SettingNameValues;
+    settingName(nextSettingName?: SettingNameValues): this;
+
+    settingValue(): () => string | null;
+    settingValue(nextSettingValue?: string | null): this;
+
+    valueName(): () => ValueName;
+    valueName(nextValueName?: ValueName): this;
+
+    valueNames(): () => ValueName[];
+    valueNames(nextValueNames?: ValueName[]): this;
+
+    modifyDomain(): () => ModifyDomainFunc;
+    modifyDomain(nextModifyDomain?: ModifyDomainFunc): this;
 
     // optional params, no idea yet if these are right or not.
     include?: (nextInclude?: number[]) => any;
@@ -102,7 +100,7 @@ export const axisFactory = (settings: Settings): AxisFactory => {
     const optionalParams = ["include", "paddingStrategy", "pad"];
     const optional = {};
 
-    const _factory: any = (data): AxisFactoryContent => {
+    const _factory: Partial<AxisFactory> = (data): AxisFactoryContent => {
         const useType = axisType(settings)
             .excludeType(excludeType)
             .settingName(settingName)
@@ -167,95 +165,75 @@ export const axisFactory = (settings: Settings): AxisFactory => {
         decorate: () => {},
     });
 
-    _factory.memoValue = <T extends Axis | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Axis, AxisFactory> => {
+    _factory.memoValue = (...args: Axis[]): any => {
         if (!args.length) {
-            return memoValue as GetSetReturn<T, Axis, AxisFactory>;
+            return memoValue;
         }
+
         memoValue = args[0];
         return _factory;
     };
 
-    _factory.excludeType = <T extends AxisTypeValues | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, AxisFactory> => {
+    _factory.excludeType = (...args: AxisTypeValues[]): any => {
         if (!args.length) {
-            return excludeType as GetSetReturn<T, string, AxisFactory>;
+            return excludeType;
         }
+
         excludeType = args[0];
         return _factory;
     };
 
-    _factory.orient = <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Orientation, AxisFactory> => {
+    _factory.orient = (...args: Orientation[]): any => {
         if (!args.length) {
-            return orient as GetSetReturn<T, Orientation, AxisFactory>;
+            return orient;
         }
+
         orient = args[0];
         return _factory;
     };
 
-    _factory.settingName = <
-        T extends SettingNameValues | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, SettingNameValues, AxisFactory> => {
+    _factory.settingName = (...args: SettingNameValues[]): any => {
         if (!args.length) {
-            return settingName as GetSetReturn<
-                T,
-                SettingNameValues,
-                AxisFactory
-            >;
+            return settingName;
         }
+
         settingName = args[0];
         return _factory;
     };
 
-    _factory.settingValue = <T extends string | null | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string | null, AxisFactory> => {
+    _factory.settingValue = (...args: (string | null)[]): any => {
         if (!args.length) {
-            return settingValue as GetSetReturn<T, string | null, AxisFactory>;
+            return settingValue;
         }
+
         settingValue = args[0];
         return _factory;
     };
 
-    _factory.valueName = <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName, AxisFactory> => {
+    _factory.valueName = (...args: ValueName[]): any => {
         if (!args.length) {
-            return valueNames[0] as GetSetReturn<T, ValueName, AxisFactory>;
+            return valueNames[0];
         }
+
         valueNames = [args[0]];
         return _factory;
     };
 
-    _factory.valueNames = <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName[], AxisFactory> => {
+    _factory.valueNames = (...args: ValueName[][]): any => {
         if (!args.length) {
-            return valueNames as GetSetReturn<T, ValueName[], AxisFactory>;
+            return valueNames;
         }
+
         valueNames = args[0];
         return _factory;
     };
 
-    _factory.modifyDomain = <
-        T extends ModifyDomainFunc | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, ModifyDomainFunc, AxisFactory> => {
-        if (!args.length) {
-            return modifyDomain as GetSetReturn<
-                T,
-                ModifyDomainFunc,
-                AxisFactory
-            >;
+    _factory.modifyDomain = (nextModifyDomain?: ModifyDomainFunc) => {
+        if (!nextModifyDomain) {
+            return modifyDomain;
         }
-        modifyDomain = args[0];
+
+        modifyDomain = nextModifyDomain;
         return _factory;
     };
 
@@ -269,5 +247,5 @@ export const axisFactory = (settings: Settings): AxisFactory => {
         };
     });
 
-    return _factory;
+    return _factory as AxisFactory;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/axisLabel.ts b/packages/perspective-viewer-d3fc/src/ts/axis/axisLabel.ts
index 7b0fa87afa..4c578429fa 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/axisLabel.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/axisLabel.ts
@@ -16,7 +16,7 @@ import { labelFunction as noLabel } from "./noAxis";
 import { labelFunction as timeLabel } from "./timeAxis";
 import { labelFunction as linearLabel } from "./linearAxis";
 import { labelFunction as ordinalLabel } from "./ordinalAxis";
-import { GetSetReturn, Settings } from "../types";
+import { Settings } from "../types";
 
 const labelFunctions = {
     none: noLabel,
@@ -28,30 +28,28 @@ const labelFunctions = {
 export interface LabelFunction {
     // NOTE: this "i" is not used...
     (d, i?: any): string;
-    valueName: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, LabelFunction>;
+    valueName(): string;
+    valueName(nextValueName: string): this;
 }
 
 export const labelFunction = (settings: Settings): LabelFunction => {
     const base = axisType(settings);
     let valueName = "__ROW_PATH__";
 
-    const label: any = (d, _i) => {
+    const label: Partial<LabelFunction> = (d, _i) => {
         return labelFunctions[base()](valueName)(d);
     };
 
     rebindAll(label, base);
 
-    label.valueName = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, LabelFunction> => {
+    label.valueName = (...args: string[]): any => {
         if (!args.length) {
-            return valueName as GetSetReturn<T, string, LabelFunction>;
+            return valueName;
         }
+
         valueName = args[0];
         return label;
     };
 
-    return label;
+    return label as LabelFunction;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/axisSplitter.ts b/packages/perspective-viewer-d3fc/src/ts/axis/axisSplitter.ts
index 6259c320ad..fded479783 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/axisSplitter.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/axisSplitter.ts
@@ -10,21 +10,22 @@
 // ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
-import { GetSetReturn, Settings } from "../types";
+import { Settings } from "../types";
 import { splitterLabels } from "./splitterLabels";
 
 export interface AxisSplitter {
     (selection: any): void;
-    color: <T extends d3.ScaleOrdinal<string, unknown> | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, d3.ScaleOrdinal<string, unknown>, AxisSplitter>;
+
+    color(): d3.ScaleOrdinal<string, unknown>;
+    color(nextColor: d3.ScaleOrdinal<string, unknown>): AxisSplitter;
+
     haveSplit: () => boolean;
-    data: <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, any[], AxisSplitter>;
-    altData: <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, any[], AxisSplitter>;
+
+    data(): any[];
+    data(nextData: any[]): AxisSplitter;
+
+    altData(): any[];
+    altData(nextData: any[]): AxisSplitter;
 }
 
 export const axisSplitter = (
@@ -74,17 +75,9 @@ export const axisSplitter = (
             .call(labeller().labels(altLabels).alt(true));
     };
 
-    splitter.color = <
-        T extends d3.ScaleOrdinal<string, unknown> | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, d3.ScaleOrdinal<string, unknown>, AxisSplitter> => {
+    splitter.color = (...args: d3.ScaleOrdinal<string, unknown>[]): any => {
         if (!args.length) {
-            return color as GetSetReturn<
-                T,
-                d3.ScaleOrdinal<string, unknown>,
-                AxisSplitter
-            >;
+            return color;
         }
         color = args[0];
         return splitter;
@@ -92,20 +85,17 @@ export const axisSplitter = (
 
     splitter.haveSplit = (): boolean => haveSplit;
 
-    splitter.data = <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, any[], AxisSplitter> => {
+    splitter.data = (...args: any[][]): any => {
         if (!args.length) {
-            return data as GetSetReturn<T, any[], AxisSplitter>;
+            return data;
         }
         data = args[0];
         return splitter;
     };
-    splitter.altData = <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, any[], AxisSplitter> => {
+
+    splitter.altData = (...args: any[][]): any => {
         if (!args.length) {
-            return altData as GetSetReturn<T, any[], AxisSplitter>;
+            return altData;
         }
         altData = args[0];
         return splitter;
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/axisType.ts b/packages/perspective-viewer-d3fc/src/ts/axis/axisType.ts
index d6cd4bc2ec..957bca9dad 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/axisType.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/axisType.ts
@@ -10,7 +10,7 @@
 // ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
-import { GetSetReturn, Settings, SettingNameValues } from "../types";
+import { Settings, SettingNameValues } from "../types";
 
 export const AXIS_TYPES = {
     none: "none",
@@ -23,15 +23,15 @@ export type AxisTypeValues = typeof AXIS_TYPES[keyof typeof AXIS_TYPES];
 
 export interface AxisType {
     (): AxisTypeValues;
-    settingName: <T extends SettingNameValues | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, SettingNameValues, AxisType>;
-    settingValue: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, AxisType>;
-    excludeType: <T extends AxisTypeValues | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, AxisTypeValues, AxisType>;
+
+    settingName(): SettingNameValues;
+    settingName(nextSettingName: SettingNameValues): this;
+
+    settingValue(): string;
+    settingValue(nextSettingValue: string): this;
+
+    excludeType(): AxisTypeValues;
+    excludeType(nextExcludeType: AxisTypeValues): this;
 }
 
 export const axisType = (settings: Settings): AxisType => {
@@ -39,7 +39,7 @@ export const axisType = (settings: Settings): AxisType => {
     let settingValue = null;
     let excludeType = null;
 
-    const getType: any = (): AxisTypeValues | boolean => {
+    const getType: Partial<AxisType> = (): AxisTypeValues | boolean => {
         const checkTypes = (types) => {
             const list = settingValue
                 ? settings[settingName].filter((s) => settingValue == s.name)
@@ -74,35 +74,30 @@ export const axisType = (settings: Settings): AxisType => {
         return AXIS_TYPES.ordinal;
     };
 
-    getType.settingName = <T extends SettingNameValues | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, SettingNameValues, AxisType> => {
+    getType.settingName = (...args: SettingNameValues[]): any => {
         if (!args.length) {
-            return settingName as GetSetReturn<T, SettingNameValues, AxisType>;
+            return settingName;
         }
         settingName = args[0];
         return getType;
     };
 
-    getType.settingValue = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, AxisType> => {
+    getType.settingValue = (...args: (string | undefined)[]): any => {
         if (!args.length) {
-            return settingValue as GetSetReturn<T, string, AxisType>;
+            return settingValue;
         }
+
         settingValue = args[0];
         return getType;
     };
 
-    getType.excludeType = <T extends AxisTypeValues | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, AxisTypeValues, AxisType> => {
+    getType.excludeType = (...args: AxisTypeValues[]): any => {
         if (!args.length) {
-            return excludeType as GetSetReturn<T, AxisTypeValues, AxisType>;
+            return excludeType;
         }
         excludeType = args[0];
         return getType;
     };
 
-    return getType;
+    return getType as AxisType;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/linearAxis.ts b/packages/perspective-viewer-d3fc/src/ts/axis/linearAxis.ts
index 59e0b96166..92ace9fd93 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/linearAxis.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/linearAxis.ts
@@ -20,7 +20,6 @@ import {
     Component,
     ComponentData,
     Domain,
-    GetSetReturn,
     PaddingStrategy,
     Settings,
     ValueName,
@@ -66,20 +65,17 @@ export const domain = (): Domain => {
         }
     };
 
-    _domain.valueName = <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName, Domain> => {
+    _domain.valueName = (...args: ValueName[]): any => {
         if (!args.length) {
-            return valueNames[0] as GetSetReturn<T, ValueName, Domain>;
+            return valueNames[0];
         }
         valueNames = [args[0]];
         return _domain;
     };
-    _domain.valueNames = <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName[], Domain> => {
+
+    _domain.valueNames = (...args: ValueName[][]): any => {
         if (!args.length) {
-            return valueNames as GetSetReturn<T, ValueName[], Domain>;
+            return valueNames;
         }
         valueNames = args[0];
         return _domain;
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/minBandwidth.ts b/packages/perspective-viewer-d3fc/src/ts/axis/minBandwidth.ts
index 42df2c3ea1..169952842f 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/minBandwidth.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/minBandwidth.ts
@@ -11,32 +11,27 @@
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
 import { rebindAll } from "d3fc";
-import { GetSetReturn } from "../types";
 
 const MIN_BANDWIDTH = 1;
 
 export interface MinBandwidth {
     (arg: any): any;
+    bandwidth(): number;
+    bandwidth(...args: any[]): any;
 }
 
 // NOTE: Can the minBandwidth in barSeries.ts be merged with this?
 
 export default (adaptee: d3.ScaleBand<string>): MinBandwidth => {
-    const minBandwidth: any = (arg) => {
+    const minBandwidth: Partial<MinBandwidth> = (arg) => {
         return adaptee(arg);
     };
 
     rebindAll(minBandwidth, adaptee);
 
-    minBandwidth.bandwidth = <T extends number | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, number, MinBandwidth> => {
+    minBandwidth.bandwidth = (...args: any[]): any => {
         if (!args.length) {
-            return Math.max(adaptee.bandwidth(), MIN_BANDWIDTH) as GetSetReturn<
-                T,
-                number,
-                MinBandwidth
-            >;
+            return Math.max(adaptee.bandwidth(), MIN_BANDWIDTH);
         }
         // NOTE: d3.ScaleBand only has a getter for .bandwidth? (no args...);
         //       I'm not sure this can be set.
@@ -45,5 +40,5 @@ export default (adaptee: d3.ScaleBand<string>): MinBandwidth => {
         return minBandwidth;
     };
 
-    return minBandwidth;
+    return minBandwidth as MinBandwidth;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/noAxis.ts b/packages/perspective-viewer-d3fc/src/ts/axis/noAxis.ts
index 53fcdd9782..738669cc74 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/noAxis.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/noAxis.ts
@@ -14,7 +14,7 @@ import * as d3 from "d3";
 import { flattenArray } from "./flatten";
 import minBandwidth from "./minBandwidth";
 import withoutTicks from "./withoutTicks";
-import { Domain, GetSetReturn, Orientation, ValueName } from "../types";
+import { Domain, Orientation, ValueName } from "../types";
 
 export const scale = () => withoutTicks(minBandwidth(d3.scaleBand()));
 
@@ -22,7 +22,7 @@ export const domain = (): Domain => {
     let valueNames = ["crossValue"];
     let orient = "horizontal";
 
-    const _domain: any = (data: any[]) => {
+    const _domain: Partial<Domain> = (data: any[]) => {
         const flattenedData = flattenArray(data);
         return transformDomain([
             ...new Set(flattenedData.map((d) => d[valueNames[0]])),
@@ -31,36 +31,31 @@ export const domain = (): Domain => {
 
     const transformDomain = (d) => (orient == "vertical" ? d.reverse() : d);
 
-    _domain.valueName = <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName, Domain> => {
+    _domain.valueName = (...args: ValueName[]): any => {
         if (!args.length) {
-            return valueNames[0] as GetSetReturn<T, ValueName, Domain>;
+            return valueNames[0];
         }
         valueNames = [args[0]];
         return _domain;
     };
-    _domain.valueNames = <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName[], Domain> => {
+
+    _domain.valueNames = (...args: ValueName[][]): any => {
         if (!args.length) {
-            return valueNames as GetSetReturn<T, ValueName[], Domain>;
+            return valueNames;
         }
         valueNames = args[0];
         return _domain;
     };
 
-    _domain.orient = <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Orientation, Domain> => {
+    _domain.orient = (...args: Orientation[]): any => {
         if (!args.length) {
-            return orient as GetSetReturn<T, Orientation, Domain>;
+            return orient;
         }
         orient = args[0];
         return _domain;
     };
 
-    return _domain;
+    return _domain as Domain;
 };
 
 export const labelFunction = (valueName) => (d) => d[valueName].join("|");
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/ordinalAxis.ts b/packages/perspective-viewer-d3fc/src/ts/axis/ordinalAxis.ts
index 78cdf959b3..e475d61b94 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/ordinalAxis.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/ordinalAxis.ts
@@ -24,7 +24,7 @@ import { getChartContainer } from "../plugin/root";
 import {
     Component,
     ComponentData,
-    GetSetReturn,
+    Domain,
     Orientation,
     SettingNameValues,
     Settings,
@@ -38,22 +38,22 @@ export const scale = () => minBandwidth(d3.scaleBand()).padding(0.5);
 
 interface OrdinalAxisDomain {
     (data: any): any;
-    valueName: <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName, OrdinalAxisDomain>;
-    valueNames: <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName[], OrdinalAxisDomain>;
-    orient: <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Orientation, OrdinalAxisDomain>;
+
+    valueName(): ValueName;
+    valueName(nextValueName: ValueName): this;
+
+    valueNames(): ValueName[];
+    valueNames(nextValueNames: ValueName[]): this;
+
+    orient(): Orientation;
+    orient(nextOrient: Orientation): this;
 }
 
 export const domain = (): OrdinalAxisDomain => {
     let valueNames = ["crossValue"];
     let orient = "horizontal";
 
-    const _domain: any = (data) => {
+    const _domain: Partial<Domain> = (data) => {
         const flattenedData = flattenArray(data);
         return transformDomain([
             ...Array.from(new Set(flattenedData.map((d) => d[valueNames[0]]))),
@@ -62,44 +62,31 @@ export const domain = (): OrdinalAxisDomain => {
 
     const transformDomain = (d) => (orient == "vertical" ? d.reverse() : d);
 
-    _domain.valueName = <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName, OrdinalAxisDomain> => {
+    _domain.valueName = (...args: ValueName[]): any => {
         if (!args.length) {
-            return valueNames[0] as GetSetReturn<
-                T,
-                ValueName,
-                OrdinalAxisDomain
-            >;
+            return valueNames[0];
         }
         valueNames = [args[0]];
         return _domain;
     };
-    _domain.valueNames = <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName[], OrdinalAxisDomain> => {
+
+    _domain.valueNames = (...args: ValueName[][]): any => {
         if (!args.length) {
-            return valueNames as GetSetReturn<
-                T,
-                ValueName[],
-                OrdinalAxisDomain
-            >;
+            return valueNames;
         }
         valueNames = args[0];
         return _domain;
     };
 
-    _domain.orient = <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Orientation, OrdinalAxisDomain> => {
+    _domain.orient = (...args: Orientation[]): any => {
         if (!args.length) {
-            return orient as GetSetReturn<T, Orientation, OrdinalAxisDomain>;
+            return orient;
         }
         orient = args[0];
         return _domain;
     };
 
-    return _domain;
+    return _domain as Domain;
 };
 
 export const labelFunction =
@@ -331,33 +318,25 @@ export const component = (settings: Settings): Component => {
         });
     };
 
-    getComponent.orient = <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Orientation, Component> => {
+    getComponent.orient = (...args: Orientation[]): any => {
         if (!args.length) {
-            return orient as GetSetReturn<T, Orientation, Component>;
+            return orient;
         }
         orient = args[0];
         return getComponent;
     };
 
-    getComponent.settingName = <
-        T extends SettingNameValues | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, SettingNameValues, Component> => {
+    getComponent.settingName = (...args: SettingNameValues[]): any => {
         if (!args.length) {
-            return settingName as GetSetReturn<T, SettingNameValues, Component>;
+            return settingName;
         }
         settingName = args[0];
         return getComponent;
     };
 
-    getComponent.domain = <T extends string[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string[], Component> => {
+    getComponent.domain = (...args: string[][]): any => {
         if (!args.length) {
-            return domain as GetSetReturn<T, string[], Component>;
+            return domain;
         }
         domain = args[0];
         return getComponent;
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/splitterLabels.ts b/packages/perspective-viewer-d3fc/src/ts/axis/splitterLabels.ts
index a940d06dc1..7712c82d91 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/splitterLabels.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/splitterLabels.ts
@@ -13,7 +13,7 @@
 import * as fc from "d3fc";
 import { getChartElement } from "../plugin/root";
 import { withoutOpacity } from "../series/seriesColors.js";
-import { GetSetReturn, HTMLSelection, Settings } from "../types";
+import { HTMLSelection, Settings } from "../types";
 
 export type SplitterLabel = {
     index: number;
@@ -22,15 +22,15 @@ export type SplitterLabel = {
 
 export interface SplitterLabels {
     (selection: any): void;
-    labels: <T extends SplitterLabel[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, any[], SplitterLabels>;
-    color: <T extends d3.ScaleOrdinal<string, unknown> | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, d3.ScaleOrdinal<string, unknown>, SplitterLabels>;
-    alt: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, SplitterLabels>;
+
+    labels(): SplitterLabel[];
+    labels(labels: SplitterLabel[]): SplitterLabels;
+
+    color(): d3.ScaleOrdinal<string, unknown>;
+    color(nextColor: d3.ScaleOrdinal<string, unknown>): SplitterLabels;
+
+    alt(): boolean;
+    alt(nextAlt: boolean): SplitterLabels;
 }
 
 // Render a set of labels with the little left/right arrows for moving
@@ -40,7 +40,7 @@ export const splitterLabels = (settings: Settings): SplitterLabels => {
     let alt = false;
     let color;
 
-    const _render: any = (selection: HTMLSelection) => {
+    const _render: Partial<SplitterLabels> = (selection: HTMLSelection) => {
         selection.text("");
 
         const labelDataJoin = fc
@@ -83,20 +83,16 @@ export const splitterLabels = (settings: Settings): SplitterLabels => {
         chartElement._draw();
     };
 
-    _render.labels = <T extends SplitterLabel[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, SplitterLabel[], SplitterLabels> => {
+    _render.labels = (...args: SplitterLabel[][]): any => {
         if (!args.length) {
-            return labels as GetSetReturn<T, SplitterLabel[], SplitterLabels>;
+            return labels;
         }
         labels = args[0];
         return _render;
     };
-    _render.alt = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, SplitterLabels> => {
+    _render.alt = (...args: boolean[]): any => {
         if (!args.length) {
-            return alt as GetSetReturn<T, boolean, SplitterLabels>;
+            return alt;
         }
         alt = args[0];
         return _render;
@@ -109,5 +105,6 @@ export const splitterLabels = (settings: Settings): SplitterLabels => {
         color = args[0];
         return _render;
     };
-    return _render;
+
+    return _render as SplitterLabels;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/axis/timeAxis.ts b/packages/perspective-viewer-d3fc/src/ts/axis/timeAxis.ts
index a6c2a8163b..ea20e70f0e 100644
--- a/packages/perspective-viewer-d3fc/src/ts/axis/timeAxis.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/axis/timeAxis.ts
@@ -13,7 +13,7 @@
 import * as d3 from "d3";
 import * as fc from "d3fc";
 import { flattenArray } from "./flatten";
-import { Domain, GetSetReturn, ValueName } from "../types";
+import { Domain, ValueName } from "../types";
 
 export const scale = () => d3.scaleTime();
 
@@ -22,7 +22,7 @@ export const domain = (): Domain => {
 
     let valueNames = ["crossValue"];
 
-    const _domain: any = (data) => {
+    const _domain: Partial<Domain> = (data) => {
         base.accessors(valueNames.map((v) => (d) => new Date(d[v])));
 
         return getDataExtent(flattenArray(data));
@@ -51,26 +51,23 @@ export const domain = (): Domain => {
         return base.padUnit("domain").pad([dataWidth / 2, dataWidth / 2])(data);
     };
 
-    _domain.valueName = <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName, Domain> => {
+    _domain.valueName = (...args: ValueName[]): any => {
         if (!args.length) {
-            return valueNames[0] as GetSetReturn<T, ValueName, Domain>;
+            return valueNames[0];
         }
         valueNames = [args[0]];
         return _domain;
     };
-    _domain.valueNames = <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ValueName[], Domain> => {
+
+    _domain.valueNames = (...args: ValueName[][]): any => {
         if (!args.length) {
-            return valueNames as GetSetReturn<T, ValueName[], Domain>;
+            return valueNames;
         }
         valueNames = args[0];
         return _domain;
     };
 
-    return _domain;
+    return _domain as Domain;
 };
 
 export const labelFunction = (valueName) => (d) => new Date(d[valueName][0]);
diff --git a/packages/perspective-viewer-d3fc/src/ts/charts/xy-scatter.ts b/packages/perspective-viewer-d3fc/src/ts/charts/xy-scatter.ts
index 62d9d7ae15..4cbf419467 100644
--- a/packages/perspective-viewer-d3fc/src/ts/charts/xy-scatter.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/charts/xy-scatter.ts
@@ -32,7 +32,7 @@ import { D3Scale, HTMLSelection, Settings } from "../types";
  * @param {any} settings
  * @param {d3.ScaleOrdinal} symbols
  */
-function overrideSymbols(settings, symbols): D3Scale {
+function overrideSymbols(settings: Settings, symbols): D3Scale {
     if (!symbols) {
         return;
     }
diff --git a/packages/perspective-viewer-d3fc/src/ts/d3fc/axis/multi-axis.ts b/packages/perspective-viewer-d3fc/src/ts/d3fc/axis/multi-axis.ts
index fd41838528..27a0bc4c0f 100644
--- a/packages/perspective-viewer-d3fc/src/ts/d3fc/axis/multi-axis.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/d3fc/axis/multi-axis.ts
@@ -21,30 +21,30 @@ import {
     exclude,
 } from "d3fc";
 import store from "./store";
-import { GetSetReturn, Orient } from "../../types";
+import { Orient } from "../../types";
 
 export interface MultiAxis {
     (selection: any): void;
-    tickSize: <T extends number | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, number, MultiAxis>;
-    tickSizeInner: <T extends number | number[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, number | number[], MultiAxis>;
-    tickSizeOuter: <T extends number | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, number, MultiAxis>;
-    decorate: <T extends any | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, any, MultiAxis>;
-    groups: <T extends any | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, any, MultiAxis>;
+
+    tickSize(): number;
+    tickSize(nextTickSize: number): MultiAxis;
+
+    tickSizeInner(): number | number[];
+    tickSizeInner(nextTickSize: number | number[]): MultiAxis;
+
+    tickSizeOuter(): number;
+    tickSizeOuter(nextTickSize: number): MultiAxis;
+
+    decorate(): any;
+    decorate(nextDecorator: any): MultiAxis;
+
+    groups(): any;
+    groups(nextGroups: any): MultiAxis;
 }
 
 const multiAxis = (orient: Orient, baseAxis, scale): MultiAxis => {
     let tickSizeOuter = 6;
-    let tickSizeInner = 6;
+    let tickSizeInner: number | number[] = 6;
     let axisStore = store(
         "tickFormat",
         "ticks",
@@ -67,7 +67,7 @@ const multiAxis = (orient: Orient, baseAxis, scale): MultiAxis => {
 
     const isVertical = () => orient === "left" || orient === "right";
 
-    const multiAxis: any = (selection) => {
+    const multiAxis: Partial<MultiAxis> = (selection) => {
         if (!groups) {
             axisStore(baseAxis(scale).decorate(decorate))(selection);
             return;
@@ -153,7 +153,7 @@ const multiAxis = (orient: Orient, baseAxis, scale): MultiAxis => {
         return customScale;
     };
 
-    multiAxis.tickSize = (...args) => {
+    multiAxis.tickSize = (...args): any => {
         if (!args.length) {
             return tickSizeInner;
         }
@@ -161,27 +161,23 @@ const multiAxis = (orient: Orient, baseAxis, scale): MultiAxis => {
         return multiAxis;
     };
 
-    multiAxis.tickSizeInner = <T extends number | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, number, MultiAxis> => {
+    multiAxis.tickSizeInner = (...args: (number | number[])[]): any => {
         if (!args.length) {
-            return tickSizeInner as GetSetReturn<T, number, MultiAxis>;
+            return tickSizeInner;
         }
         tickSizeInner = Array.isArray(args[0]) ? args[0] : Number(args[0]);
         return multiAxis;
     };
 
-    multiAxis.tickSizeOuter = <T extends number | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, number, MultiAxis> => {
+    multiAxis.tickSizeOuter = (...args: number[]): any => {
         if (!args.length) {
-            return tickSizeOuter as GetSetReturn<T, number, MultiAxis>;
+            return tickSizeOuter;
         }
         tickSizeOuter = Number(args[0]);
         return multiAxis;
     };
 
-    multiAxis.decorate = (...args) => {
+    multiAxis.decorate = (...args): any => {
         if (!args.length) {
             return decorate;
         }
@@ -199,7 +195,7 @@ const multiAxis = (orient: Orient, baseAxis, scale): MultiAxis => {
 
     rebindAll(multiAxis, axisStore);
 
-    return multiAxis;
+    return multiAxis as MultiAxis;
 };
 
 export const multiAxisTop = (scale) => multiAxis("top", axisOrdinalTop, scale);
diff --git a/packages/perspective-viewer-d3fc/src/ts/d3fc/extent/extentLinear.ts b/packages/perspective-viewer-d3fc/src/ts/d3fc/extent/extentLinear.ts
index 0f4932bfb9..05a50779d0 100644
--- a/packages/perspective-viewer-d3fc/src/ts/d3fc/extent/extentLinear.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/d3fc/extent/extentLinear.ts
@@ -12,22 +12,28 @@
 
 import * as d3Array from "d3-array";
 import { defaultPadding } from "../padding/default";
-import { GetSetReturn, Pad, PadUnit, PaddingStrategy } from "../../types";
+import { Pad, PadUnit, PaddingStrategy } from "../../types";
 
 export type SymmetricalAbout = number | null;
 
 export interface ExtentLinear {
     (data: any[]): PaddingStrategy;
     accessors: (nextAccessors?: any[]) => any;
-    pad: <T extends Pad | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Pad, ExtentLinear>;
-    padUnit: <T extends PadUnit | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, PadUnit, ExtentLinear>;
-    include: (nextInclude?: number[]) => any;
-    symmetricalAbout: (nextSymmetricalAbout?: number | null) => any;
-    paddingStrategy: (nextPaddingStrategy?: any) => any;
+
+    pad(): Pad;
+    pad(nextPad: Pad): ExtentLinear;
+
+    padUnit(): PadUnit;
+    padUnit(nextPadUnit: PadUnit): ExtentLinear;
+
+    include(): number[];
+    include(nextInclude?: number[]): ExtentLinear;
+
+    symmetricalAbout(): number | null;
+    symmetricalAbout(nextSymmetricalAbout?: number | null): ExtentLinear;
+
+    paddingStrategy(): PaddingStrategy;
+    paddingStrategy(nextPaddingStrategy?: any): ExtentLinear;
 }
 
 export const extentLinear = function (): ExtentLinear {
@@ -40,7 +46,9 @@ export const extentLinear = function (): ExtentLinear {
     let include: number[] = [];
     let paddingStrategy = defaultPadding();
 
-    const instance: any = function instance(data): PaddingStrategy {
+    const instance: Partial<ExtentLinear> = function instance(
+        data
+    ): PaddingStrategy {
         let values = new Array(data.length);
         let _iteratorNormalCompletion = true;
         let _didIteratorError = false;
@@ -116,11 +124,9 @@ export const extentLinear = function (): ExtentLinear {
 
     //This function points directly at the paddingStrategy child object's
     //properties for backwards-compatibility. DEPRECATED.
-    instance.pad = function <T extends Pad | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Pad, ExtentLinear> {
-        if (!arguments.length) {
-            return paddingStrategy.pad as GetSetReturn<T, Pad, ExtentLinear>;
+    instance.pad = function (...args: Pad[]): any {
+        if (!args.length) {
+            return paddingStrategy.pad;
         }
 
         paddingStrategy.pad(args[0]);
@@ -130,15 +136,9 @@ export const extentLinear = function (): ExtentLinear {
 
     //This function points directly at the paddingStrategy child object's
     //properties for backwards-compatibility. DEPRECATED.
-    instance.padUnit = function <T extends PadUnit | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, PadUnit, ExtentLinear> {
-        if (!arguments.length) {
-            return paddingStrategy.padUnit as GetSetReturn<
-                T,
-                PadUnit,
-                ExtentLinear
-            >;
+    instance.padUnit = function (...args: PadUnit[]): any {
+        if (!args.length) {
+            return paddingStrategy.padUnit;
         }
 
         paddingStrategy.padUnit(args[0]);
@@ -146,53 +146,37 @@ export const extentLinear = function (): ExtentLinear {
         return instance;
     };
 
-    instance.include = function <T extends number[] | undefined = undefined>(
-        nextInclude?: T
-    ): GetSetReturn<T, number[], ExtentLinear> {
-        if (!arguments.length) {
-            return include as GetSetReturn<T, number[], ExtentLinear>;
+    instance.include = function (...args: number[][]): any {
+        if (!args.length) {
+            return include;
         }
 
-        include = nextInclude;
+        include = args[0];
 
         return instance;
     };
 
-    instance.symmetricalAbout = function <
-        T extends SymmetricalAbout | undefined = undefined
-    >(
-        nextSymmetricalAbout?: SymmetricalAbout
-    ): GetSetReturn<T, SymmetricalAbout, ExtentLinear> {
-        if (!arguments.length) {
-            return symmetricalAbout as GetSetReturn<
-                T,
-                SymmetricalAbout,
-                ExtentLinear
-            >;
+    instance.symmetricalAbout = function (...args: SymmetricalAbout[]): any {
+        if (!args.length) {
+            return symmetricalAbout;
         }
 
-        symmetricalAbout = nextSymmetricalAbout;
+        symmetricalAbout = args[0];
 
         return instance;
     };
 
-    instance.paddingStrategy = function <
-        T extends PaddingStrategy | undefined = undefined
-    >(nextPaddingStrategy?: T): GetSetReturn<T, PaddingStrategy, ExtentLinear> {
-        if (!arguments.length) {
-            return paddingStrategy as GetSetReturn<
-                T,
-                PaddingStrategy,
-                ExtentLinear
-            >;
+    instance.paddingStrategy = function (...args: PaddingStrategy[]): any {
+        if (!args.length) {
+            return paddingStrategy;
         }
 
-        paddingStrategy = nextPaddingStrategy;
+        paddingStrategy = args[0];
 
         return instance;
     };
 
-    return instance;
+    return instance as ExtentLinear;
 };
 
 let toConsumableArray = function (arr) {
diff --git a/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/default.ts b/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/default.ts
index 72658f264e..55a9f003b4 100644
--- a/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/default.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/default.ts
@@ -10,13 +10,13 @@
 // ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
-import { GetSetReturn, Pad, PadUnit, PaddingStrategy } from "../../types";
+import { Pad, PadUnit, PaddingStrategy } from "../../types";
 
 export const defaultPadding = (): PaddingStrategy => {
     let pad = [0, 0];
     let padUnit: PadUnit = "percent" as const;
 
-    const padding: any = (extent) => {
+    const padding: Partial<PaddingStrategy> = (extent) => {
         switch (padUnit) {
             case "domain": {
                 extent[0] -= pad[0];
@@ -35,11 +35,9 @@ export const defaultPadding = (): PaddingStrategy => {
         return extent;
     };
 
-    padding.pad = function <T extends Pad | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Pad, PaddingStrategy> {
-        if (args.length === 0) {
-            return pad as GetSetReturn<T, Pad, PaddingStrategy>;
+    padding.pad = function (...args: Pad[]): any {
+        if (!args.length) {
+            return pad;
         }
 
         pad = args[0];
@@ -47,11 +45,9 @@ export const defaultPadding = (): PaddingStrategy => {
         return padding;
     };
 
-    padding.padUnit = function <T extends PadUnit | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, PadUnit, PaddingStrategy> {
+    padding.padUnit = function (...args: PadUnit[]): any {
         if (!args.length) {
-            return padUnit as GetSetReturn<T, PadUnit, PaddingStrategy>;
+            return padUnit;
         }
 
         padUnit = args[0];
@@ -59,5 +55,5 @@ export const defaultPadding = (): PaddingStrategy => {
         return padding;
     };
 
-    return padding;
+    return padding as PaddingStrategy;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/hardLimitZero.ts b/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/hardLimitZero.ts
index 998944a394..7bcde8b331 100644
--- a/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/hardLimitZero.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/d3fc/padding/hardLimitZero.ts
@@ -10,14 +10,14 @@
 // ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
-import { GetSetReturn, Pad, PadUnit, PaddingStrategy } from "../../types";
+import { Pad, PadUnit, PaddingStrategy } from "../../types";
 import { defaultPadding } from "./default";
 import * as fc from "d3fc";
 
 export const hardLimitZeroPadding = (): PaddingStrategy => {
     const _defaultPadding = defaultPadding();
 
-    const padding: any = (extent) => {
+    const padding: Partial<PaddingStrategy> = (extent) => {
         let pad = _defaultPadding.pad();
         let padUnit = _defaultPadding.padUnit();
 
@@ -46,19 +46,15 @@ export const hardLimitZeroPadding = (): PaddingStrategy => {
         return extent;
     };
 
-    padding.pad = function <T extends Pad | undefined = undefined>(
-        nextPad?: T
-    ): T extends undefined ? Pad : T extends Pad ? PaddingStrategy : never {
-        return padding;
+    padding.pad = function (..._args: Pad[]): any {
+        return _defaultPadding.pad();
     };
 
-    padding.padUnit = function <T extends PadUnit | undefined = undefined>(
-        nextPadUnit?: T
-    ): GetSetReturn<T, PadUnit, PaddingStrategy> {
-        return padding;
+    padding.padUnit = function (..._args: PadUnit[]): any {
+        return _defaultPadding.padUnit();
     };
 
     fc.rebindAll(padding, _defaultPadding);
 
-    return padding;
+    return padding as PaddingStrategy;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/gridlines/gridlines.ts b/packages/perspective-viewer-d3fc/src/ts/gridlines/gridlines.ts
index f54cef6d4b..3924493943 100644
--- a/packages/perspective-viewer-d3fc/src/ts/gridlines/gridlines.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/gridlines/gridlines.ts
@@ -11,7 +11,7 @@
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
 import * as fc from "d3fc";
-import { GetSetReturn } from "../types";
+import { D3Scale, Orientation } from "../types";
 
 const mainGridSvg = (settings) => (x) =>
     x
@@ -34,12 +34,21 @@ const crossGridCanvas = (settings) => (c) => {
 
 export interface WithGridLines {
     (...args): any;
-    orient: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, WithGridLines>;
-    canvas: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, WithGridLines>;
+
+    orient(): Orientation;
+    orient(nextOrient: Orientation): WithGridLines;
+
+    canvas(): boolean;
+    canvas(nextCanvas: boolean): WithGridLines;
+
+    xScale(): D3Scale;
+    xScale(xScale: D3Scale): WithGridLines;
+
+    yScale(): D3Scale;
+    yScale(yScale: D3Scale): WithGridLines;
+
+    context(): any;
+    context(context: any): WithGridLines;
 }
 
 export default (series, settings): WithGridLines => {
@@ -54,7 +63,7 @@ export default (series, settings): WithGridLines => {
     let mainGrid = mainGridSvg(settings);
     let crossGrid = crossGridSvg;
 
-    const _withGridLines: any = function (...args) {
+    const _withGridLines: Partial<WithGridLines> = function (...args) {
         if (canvas) {
             seriesMulti = fc.seriesCanvasMulti().context(context);
             annotationGridline = fc.annotationCanvasGridline();
@@ -74,7 +83,7 @@ export default (series, settings): WithGridLines => {
         return multi.series([gridlines, series])(...args);
     };
 
-    _withGridLines.orient = (...args) => {
+    _withGridLines.orient = (...args: Orientation[]): any => {
         if (!args.length) {
             return orient;
         }
@@ -82,17 +91,15 @@ export default (series, settings): WithGridLines => {
         return _withGridLines;
     };
 
-    _withGridLines.canvas = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, WithGridLines> => {
+    _withGridLines.canvas = (...args: boolean[]): any => {
         if (!args.length) {
-            return canvas as GetSetReturn<T, boolean, WithGridLines>;
+            return canvas;
         }
         canvas = args[0];
         return _withGridLines;
     };
 
-    _withGridLines.xScale = (...args) => {
+    _withGridLines.xScale = (...args): any => {
         if (!args.length) {
             return xScale;
         }
@@ -100,7 +107,7 @@ export default (series, settings): WithGridLines => {
         return _withGridLines;
     };
 
-    _withGridLines.yScale = (...args) => {
+    _withGridLines.yScale = (...args): any => {
         if (!args.length) {
             return yScale;
         }
@@ -108,7 +115,7 @@ export default (series, settings): WithGridLines => {
         return _withGridLines;
     };
 
-    _withGridLines.context = (...args) => {
+    _withGridLines.context = (...args): any => {
         if (!args.length) {
             return context;
         }
@@ -116,5 +123,5 @@ export default (series, settings): WithGridLines => {
         return _withGridLines;
     };
 
-    return _withGridLines;
+    return _withGridLines as WithGridLines;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/layout/gridLayoutMultiChart.ts b/packages/perspective-viewer-d3fc/src/ts/layout/gridLayoutMultiChart.ts
index 2cf5ed1ccd..d87bc482f6 100644
--- a/packages/perspective-viewer-d3fc/src/ts/layout/gridLayoutMultiChart.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/layout/gridLayoutMultiChart.ts
@@ -10,23 +10,19 @@
 // ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
 // ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
 
-import { GetSetReturn } from "../types";
 import { getOrCreateElement } from "../utils/utils";
 
 export interface GridLayoutMultiChart {
     (container: any): any;
 
-    elementsPrefix: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, GridLayoutMultiChart>;
+    elementsPrefix(): string;
+    elementsPrefix(nextPrefix: string): GridLayoutMultiChart;
 
-    padding: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, GridLayoutMultiChart>;
+    padding(): string;
+    padding(nextPadding: string): GridLayoutMultiChart;
 
-    svg: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, GridLayoutMultiChart>;
+    svg(): boolean;
+    svg(nextSvg: boolean): GridLayoutMultiChart;
 
     chartContainer: () => any;
     chartEnter: () => any;
@@ -47,7 +43,9 @@ export function gridLayoutMultiChart(): GridLayoutMultiChart {
     let svg = true;
     let padding = null;
 
-    const _gridLayoutMultiChart: any = (container) => {
+    const _gridLayoutMultiChart: Partial<GridLayoutMultiChart> = (
+        container
+    ) => {
         const outerContainer = getOrCreateElement(
             container,
             "div.outer-container",
@@ -139,36 +137,24 @@ export function gridLayoutMultiChart(): GridLayoutMultiChart {
         }
     };
 
-    _gridLayoutMultiChart.padding = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, GridLayoutMultiChart> => {
+    _gridLayoutMultiChart.padding = (...args: string[]): any => {
         if (!args.length) {
-            return padding as GetSetReturn<T, string, GridLayoutMultiChart>;
+            return padding;
         }
         padding = args[0];
         return _gridLayoutMultiChart;
     };
-    _gridLayoutMultiChart.svg = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, GridLayoutMultiChart> => {
+    _gridLayoutMultiChart.svg = (...args: boolean[]): any => {
         if (!args.length) {
-            return svg as GetSetReturn<T, boolean, GridLayoutMultiChart>;
+            return svg;
         }
         svg = args[0];
         return _gridLayoutMultiChart;
     };
 
-    _gridLayoutMultiChart.elementsPrefix = <
-        T extends string | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, string, GridLayoutMultiChart> => {
+    _gridLayoutMultiChart.elementsPrefix = (...args: string[]): any => {
         if (!args.length) {
-            return elementsPrefix as GetSetReturn<
-                T,
-                string,
-                GridLayoutMultiChart
-            >;
+            return elementsPrefix;
         }
         elementsPrefix = args[0];
         return _gridLayoutMultiChart;
@@ -184,5 +170,5 @@ export function gridLayoutMultiChart(): GridLayoutMultiChart {
 
     _gridLayoutMultiChart.containerSize = () => containerSize;
 
-    return _gridLayoutMultiChart;
+    return _gridLayoutMultiChart as GridLayoutMultiChart;
 }
diff --git a/packages/perspective-viewer-d3fc/src/ts/legend/legend.ts b/packages/perspective-viewer-d3fc/src/ts/legend/legend.ts
index 62e2f891b9..a6dbc57557 100644
--- a/packages/perspective-viewer-d3fc/src/ts/legend/legend.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/legend/legend.ts
@@ -16,7 +16,7 @@ import scrollableLegend from "./scrollableLegend";
 import { withoutOpacity } from "../series/seriesColors";
 import { getChartElement } from "../plugin/root";
 import { getOrCreateElement } from "../utils/utils";
-import { D3Scale, GetSetReturn } from "../types";
+import { D3Scale } from "../types";
 
 export type LegendComponentSettings = {
     hideKeys?: any[];
@@ -52,15 +52,15 @@ function symbolScale(fromScale) {
 
 interface LegendComponent {
     (container): void;
-    settings: <T extends LegendComponentSettings | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, LegendComponentSettings, LegendComponent>;
-    scale: <T extends D3Scale | null | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale | null, LegendComponent>;
-    color: <T extends d3.ScaleOrdinal<string, unknown> | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, d3.ScaleOrdinal<string, unknown>, LegendComponent>;
+
+    settings(): LegendComponentSettings;
+    settings(nextSettings: LegendComponentSettings): LegendComponent;
+
+    scale(): D3Scale | null;
+    scale(nextScale: D3Scale | null): LegendComponent;
+
+    color(): d3.ScaleOrdinal<string, unknown>;
+    color(nextColor: d3.ScaleOrdinal<string, unknown>): LegendComponent;
 }
 
 function legendComponent(
@@ -71,7 +71,7 @@ function legendComponent(
     let scale = null; // type?
     let color: D3Scale | null = null;
 
-    const legend: any = (container) => {
+    const legend: Partial<LegendComponent> = (container) => {
         if (scale && scale.range().length > 1) {
             const scrollLegend = scrollLegendComponent(settings);
             scrollLegend
@@ -136,42 +136,30 @@ function legendComponent(
         }
     };
 
-    legend.settings = <
-        T extends LegendComponentSettings | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, LegendComponentSettings, LegendComponent> => {
+    legend.settings = (...args: LegendComponentSettings[]): any => {
         if (args.length === 0) {
-            return settings as GetSetReturn<
-                T,
-                LegendComponentSettings,
-                LegendComponent
-            >;
+            return settings;
         }
         settings = args[0];
 
         return legend;
     };
 
-    legend.scale = <T extends D3Scale | null | undefined = undefined>(
-        ...args
-    ): GetSetReturn<T, D3Scale | null, LegendComponent> => {
+    legend.scale = (...args: (D3Scale | null)[]): any => {
         if (!args.length) {
-            return scale as GetSetReturn<T, D3Scale | null, LegendComponent>;
+            return scale;
         }
         scale = scaleModifier ? scaleModifier(args[0]) : args[0];
         return legend;
     };
 
-    legend.color = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, LegendComponent> => {
+    legend.color = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return color as GetSetReturn<T, D3Scale, LegendComponent>;
+            return color;
         }
         color = args[0];
         return legend;
     };
 
-    return legend;
+    return legend as LegendComponent;
 }
diff --git a/packages/perspective-viewer-d3fc/src/ts/series/seriesColors.ts b/packages/perspective-viewer-d3fc/src/ts/series/seriesColors.ts
index 9f61061027..53540d0ae5 100644
--- a/packages/perspective-viewer-d3fc/src/ts/series/seriesColors.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/series/seriesColors.ts
@@ -13,7 +13,7 @@
 import * as d3 from "d3";
 import { groupFromKey } from "./seriesKey";
 import { getValuesByColumn } from "../data/utils";
-import { GetSetReturn, Settings } from "../types";
+import { Settings } from "../types";
 
 export function seriesColors(
     settings: Settings
@@ -60,18 +60,18 @@ type ColorScaleMapFunc = (d: any) => string;
 
 interface ColorScale {
     (): d3.ScaleOrdinal<string, unknown> | null;
-    settings: <T extends Settings | undefined = undefined>(
-        nextSettings?: T
-    ) => GetSetReturn<T, Settings, ColorScale>;
-    domain: <T extends any[] | undefined = undefined>(
-        nextDomain?: T
-    ) => GetSetReturn<T, any[], ColorScale>;
-    defaultColors: <T extends string[] | undefined = undefined>(
-        nextDefaultColors?: T
-    ) => GetSetReturn<T, string[], ColorScale>;
-    mapFunction: <T extends ColorScaleMapFunc | undefined = undefined>(
-        nextMapFunction?: T
-    ) => GetSetReturn<T, ColorScaleMapFunc, ColorScale>;
+
+    settings(): Settings;
+    settings(nextSettings: Settings): ColorScale;
+
+    domain(): any[];
+    domain(nextDomain: any[]): ColorScale;
+
+    defaultColors(): string[];
+    defaultColors(nextDefaultColors: string[]): ColorScale;
+
+    mapFunction(): ColorScaleMapFunc;
+    mapFunction(nextMapFunction: ColorScaleMapFunc): ColorScale;
 }
 
 export function colorScale(): ColorScale {
@@ -81,7 +81,7 @@ export function colorScale(): ColorScale {
     let mapFunction = (d) =>
         withOpacity(d, settings.colorStyles && settings.colorStyles.opacity);
 
-    const colors: any = (): d3.ScaleOrdinal<string, unknown> | null => {
+    const colors: ColorScale = (): d3.ScaleOrdinal<string, unknown> | null => {
         const styles = settings.colorStyles;
         const defaults = defaultColors || [styles.series];
         if (defaults || domain.length > 1) {
@@ -91,52 +91,40 @@ export function colorScale(): ColorScale {
         return null;
     };
 
-    colors.domain = <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, any[], ColorScale> => {
+    colors.domain = (...args: any[][]): any => {
         if (args.length === 0) {
-            return domain as GetSetReturn<T, any[], ColorScale>;
+            return domain;
         }
         domain = args[0];
         return colors;
     };
 
-    colors.defaultColors = <T extends string[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string[], ColorScale> => {
+    colors.defaultColors = (...args: string[][]): any => {
         if (!args.length) {
-            return defaultColors as GetSetReturn<T, string[], ColorScale>;
+            return defaultColors;
         }
         defaultColors = args[0];
         return colors;
     };
 
-    colors.mapFunction = <T extends ColorScaleMapFunc | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, ColorScaleMapFunc, ColorScale> => {
+    colors.mapFunction = (...args: ColorScaleMapFunc[]): any => {
         if (!args.length) {
-            return mapFunction as GetSetReturn<
-                T,
-                ColorScaleMapFunc,
-                ColorScale
-            >;
+            return mapFunction;
         }
         mapFunction = args[0];
         return colors;
     };
 
-    colors.settings = <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Settings, ColorScale> => {
+    colors.settings = (...args: Settings[]): any => {
         if (!args.length) {
-            return settings as GetSetReturn<T, Settings, ColorScale>;
+            return settings;
         }
         settings = args[0];
 
         return colors;
     };
 
-    return colors;
+    return colors as ColorScale;
 }
 
 export function withoutOpacity(color) {
diff --git a/packages/perspective-viewer-d3fc/src/ts/series/sunburst/sunburstSeries.ts b/packages/perspective-viewer-d3fc/src/ts/series/sunburst/sunburstSeries.ts
index 2a6aa8408d..a85ab1880a 100644
--- a/packages/perspective-viewer-d3fc/src/ts/series/sunburst/sunburstSeries.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/series/sunburst/sunburstSeries.ts
@@ -13,7 +13,7 @@
 import { drawArc, arcVisible } from "./sunburstArc";
 import { labelVisible, labelTransform, cropLabel } from "./sunburstLabel";
 import { clickHandler } from "./sunburstClick";
-import { D3Scale, GetSetReturn, Settings } from "../../types";
+import { D3Scale, Settings } from "../../types";
 
 export interface SunburstData extends d3.HierarchyNode<any> {
     children: this[];
@@ -39,25 +39,20 @@ export interface SunburstData extends d3.HierarchyNode<any> {
 export interface SunburstSeries {
     (sunburstElement: any): void;
 
-    settings: <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Settings, SunburstSeries>;
+    settings(): Settings;
+    settings(settings: Settings): SunburstSeries;
 
-    split: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, SunburstSeries>;
+    split(): string;
+    split(split: string): SunburstSeries;
 
-    data: <T extends SunburstData | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, SunburstData, SunburstSeries>;
+    data(): SunburstData;
+    data(data: SunburstData): SunburstSeries;
 
-    color: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, SunburstSeries>;
+    color(): D3Scale;
+    color(color: D3Scale): SunburstSeries;
 
-    radius: <T extends number | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, number, SunburstSeries>;
+    radius(): number;
+    radius(radius: number): SunburstSeries;
 }
 
 export function sunburstSeries(): SunburstSeries {
@@ -67,7 +62,7 @@ export function sunburstSeries(): SunburstSeries {
     let color: D3Scale | null = null;
     let radius = null;
 
-    const _sunburstSeries: any = (sunburstElement) => {
+    const _sunburstSeries: Partial<SunburstSeries> = (sunburstElement) => {
         const segment = sunburstElement
             .selectAll("g.segment")
             .data(data.descendants().slice(1));
@@ -136,55 +131,45 @@ export function sunburstSeries(): SunburstSeries {
             .on("click", (d) => onClick(d, false));
     };
 
-    _sunburstSeries.settings = <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Settings, SunburstSeries> => {
+    _sunburstSeries.settings = (...args: Settings[]): any => {
         if (!args.length) {
-            return settings as GetSetReturn<T, Settings, SunburstSeries>;
+            return settings;
         }
         settings = args[0];
         return _sunburstSeries;
     };
 
-    _sunburstSeries.split = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, SunburstSeries> => {
+    _sunburstSeries.split = (...args: string[]): any => {
         if (!args.length) {
-            return split as GetSetReturn<T, string, SunburstSeries>;
+            return split;
         }
         split = args[0];
         return _sunburstSeries;
     };
 
-    _sunburstSeries.data = <T extends SunburstData | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, SunburstData, SunburstSeries> => {
+    _sunburstSeries.data = (...args: SunburstData[]): any => {
         if (!args.length) {
-            return data as GetSetReturn<T, SunburstData, SunburstSeries>;
+            return data;
         }
         data = args[0];
         return _sunburstSeries;
     };
 
-    _sunburstSeries.color = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, SunburstSeries> => {
+    _sunburstSeries.color = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return color as GetSetReturn<T, D3Scale, SunburstSeries>;
+            return color;
         }
         color = args[0];
         return _sunburstSeries;
     };
 
-    _sunburstSeries.radius = <T extends number | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, number, SunburstSeries> => {
+    _sunburstSeries.radius = (...args: number[]): any => {
         if (!args.length) {
-            return radius as GetSetReturn<T, number, SunburstSeries>;
+            return radius;
         }
         radius = args[0];
         return _sunburstSeries;
     };
 
-    return _sunburstSeries;
+    return _sunburstSeries as SunburstSeries;
 }
diff --git a/packages/perspective-viewer-d3fc/src/ts/series/xy-scatter/xyScatterSeries.ts b/packages/perspective-viewer-d3fc/src/ts/series/xy-scatter/xyScatterSeries.ts
index 0bad3da4d0..65e9b96489 100644
--- a/packages/perspective-viewer-d3fc/src/ts/series/xy-scatter/xyScatterSeries.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/series/xy-scatter/xyScatterSeries.ts
@@ -20,7 +20,7 @@ import { hardLimitZeroPadding } from "../../d3fc/padding/hardLimitZero";
 import zoomableChart from "../../zoom/zoomableChart";
 import nearbyTip from "../../tooltip/nearbyTip";
 import { symbolsObj } from "../seriesSymbols";
-import { D3Scale, GetSetReturn, Settings } from "../../types";
+import { D3Scale, Settings } from "../../types";
 
 /**
  * Define a clamped scaling factor based on the container size for bubble plots.
@@ -42,18 +42,18 @@ function interpolate_scale([x1, y1], [x2, y2]) {
 
 export interface XYScatterSeries {
     (container: any): void;
-    settings: <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Settings, XYScatterSeries>;
-    data: <T extends { [key: string]: any }[][] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, { [key: string]: any }[][], XYScatterSeries>;
-    color: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, XYScatterSeries>;
-    symbols: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, XYScatterSeries>;
+
+    settings(): Settings;
+    settings(settings: Settings): XYScatterSeries;
+
+    data(): Record<string, any>[][];
+    data(data: Record<string, any>[][]): XYScatterSeries;
+
+    color(): D3Scale;
+    color(color: D3Scale): XYScatterSeries;
+
+    symbols(): D3Scale;
+    symbols(symbols: D3Scale): XYScatterSeries;
 }
 
 /**
@@ -66,7 +66,7 @@ export default function xyScatterSeries(): XYScatterSeries {
     let color = null;
     let symbols = null;
 
-    const _xyScatterSeries: any = (container) => {
+    const _xyScatterSeries: Partial<XYScatterSeries> = (container) => {
         const colorBy = settings.realValues[2];
         let hasColorBy = !!colorBy;
         const symbolCol = settings.realValues[4];
@@ -154,42 +154,34 @@ export default function xyScatterSeries(): XYScatterSeries {
         container.call(toolTip);
     };
 
-    _xyScatterSeries.settings = <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Settings, XYScatterSeries> => {
+    _xyScatterSeries.settings = (...args: Settings[]): any => {
         if (!args.length) {
-            return settings as GetSetReturn<T, Settings, XYScatterSeries>;
+            return settings;
         }
         settings = args[0];
         return _xyScatterSeries;
     };
-    _xyScatterSeries.data = <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, any[], XYScatterSeries> => {
+    _xyScatterSeries.data = (...args: any[][]): any => {
         if (!args.length) {
-            return data as GetSetReturn<T, any[], XYScatterSeries>;
+            return data;
         }
         data = args[0];
         return _xyScatterSeries;
     };
-    _xyScatterSeries.color = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, XYScatterSeries> => {
+    _xyScatterSeries.color = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return color as GetSetReturn<T, D3Scale, XYScatterSeries>;
+            return color;
         }
         color = args[0];
         return _xyScatterSeries;
     };
-    _xyScatterSeries.symbols = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, XYScatterSeries> => {
+    _xyScatterSeries.symbols = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return symbols as GetSetReturn<T, D3Scale, XYScatterSeries>;
+            return symbols;
         }
         symbols = args[0];
         return _xyScatterSeries;
     };
 
-    return _xyScatterSeries;
+    return _xyScatterSeries as XYScatterSeries;
 }
diff --git a/packages/perspective-viewer-d3fc/src/ts/tooltip/nearbyTip.ts b/packages/perspective-viewer-d3fc/src/ts/tooltip/nearbyTip.ts
index 53de40c503..39a2657137 100644
--- a/packages/perspective-viewer-d3fc/src/ts/tooltip/nearbyTip.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/tooltip/nearbyTip.ts
@@ -16,7 +16,7 @@ import { withOpacity } from "../series/seriesColors.js";
 import { findBestFromData } from "../data/findBest";
 import { raiseEvent } from "./selectionEvent";
 import { SplitData } from "../data/splitData";
-import { D3Scale, GetSetReturn, Settings } from "../types";
+import { D3Scale, Settings } from "../types";
 
 export type AltDataWithScale = {
     data: SplitData[][];
@@ -30,39 +30,39 @@ export interface SizeArg {
 
 interface NearbyTip {
     (selection: any): void;
-    scaleFactor: <T extends number | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, number, NearbyTip>;
-    settings: <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Settings, NearbyTip>;
-    xScale: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, NearbyTip>;
-    yScale: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, NearbyTip>;
-    color: <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, D3Scale, NearbyTip>;
-    size: <T extends SizeArg | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, SizeArg, NearbyTip>;
-    canvas: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, NearbyTip>;
-    data: <T extends { [key: string]: any }[][] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, { [key: string]: any }[][], NearbyTip>;
-    xValueName: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, NearbyTip>;
-    yValueName: <T extends string | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, string, NearbyTip>;
-    altDataWithScale: <T extends AltDataWithScale | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, AltDataWithScale, NearbyTip>;
+
+    scaleFactor(): number;
+    scaleFactor(scaleFactor: number): NearbyTip;
+
+    settings(): Settings;
+    settings(settings: Settings): NearbyTip;
+
+    xScale(): D3Scale;
+    xScale(xScale: D3Scale): NearbyTip;
+
+    yScale(): D3Scale;
+    yScale(yScale: D3Scale): NearbyTip;
+
+    color(): D3Scale;
+    color(color: D3Scale): NearbyTip;
+
+    size(): SizeArg;
+    size(size: SizeArg): NearbyTip;
+
+    canvas(): boolean;
+    canvas(canvas: boolean): NearbyTip;
+
+    data(): Record<string, any>[][];
+    data(data: Record<string, any>[][]): NearbyTip;
+
+    xValueName(): string;
+    xValueName(xValueName: string): NearbyTip;
+
+    yValueName(): string;
+    yValueName(yValueName: string): NearbyTip;
+
+    altDataWithScale(): AltDataWithScale;
+    altDataWithScale(altDataWithScale: AltDataWithScale): NearbyTip;
 }
 
 export default (): NearbyTip => {
@@ -79,7 +79,7 @@ export default (): NearbyTip => {
     let altDataWithScale = null;
     let scale_factor = 1;
 
-    const nearbyTip: any = (selection) => {
+    const nearbyTip: Partial<NearbyTip> = (selection) => {
         const chartPlotArea = `d3fc-${canvas ? "canvas" : "svg"}.plot-area`;
         if (xScale || yScale) {
             let tooltipData = null;
@@ -173,121 +173,93 @@ export default (): NearbyTip => {
         return { data: best1, scale: yScale };
     };
 
-    nearbyTip.scaleFactor = <T extends number | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, number, NearbyTip> => {
+    nearbyTip.scaleFactor = (...args: number[]): any => {
         if (!args.length) {
-            return scale_factor as GetSetReturn<T, number, NearbyTip>;
+            return scale_factor;
         }
         scale_factor = args[0];
         return nearbyTip;
     };
-    nearbyTip.xScale = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, NearbyTip> => {
+    nearbyTip.xScale = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return xScale as GetSetReturn<T, D3Scale, NearbyTip>;
+            return xScale;
         }
         xScale = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.yScale = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, NearbyTip> => {
+    nearbyTip.yScale = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return yScale as GetSetReturn<T, D3Scale, NearbyTip>;
+            return yScale;
         }
         yScale = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.color = <T extends D3Scale | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, D3Scale, NearbyTip> => {
+    nearbyTip.color = (...args: D3Scale[]): any => {
         if (!args.length) {
-            return color as GetSetReturn<T, D3Scale, NearbyTip>;
+            return color;
         }
         color = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.size = <T extends SizeArg | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, SizeArg, NearbyTip> => {
+    nearbyTip.size = (...args: SizeArg[]): any => {
         if (!args.length) {
-            return size as GetSetReturn<T, SizeArg, NearbyTip>;
+            return size;
         }
         size = args[0] ? args[0].copy().range([40, 4000]) : null;
         return nearbyTip;
     };
 
-    nearbyTip.canvas = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, NearbyTip> => {
+    nearbyTip.canvas = (...args: boolean[]): any => {
         if (!args.length) {
-            return canvas as GetSetReturn<T, boolean, NearbyTip>;
+            return canvas;
         }
         canvas = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.data = <
-        T extends Record<string, any>[][] | undefined = undefined
-    >(
-        ...args: T[]
-    ): GetSetReturn<T, Record<string, any>[][], NearbyTip> => {
+    nearbyTip.data = (...args: Record<string, any>[][][]): any => {
         if (!args.length) {
-            return data as GetSetReturn<T, Record<string, any>[][], NearbyTip>;
+            return data;
         }
         data = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.xValueName = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, NearbyTip> => {
+    nearbyTip.xValueName = (...args: string[]): any => {
         if (!args.length) {
-            return xValueName as GetSetReturn<T, string, NearbyTip>;
+            return xValueName;
         }
         xValueName = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.yValueName = <T extends string | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, string, NearbyTip> => {
+    nearbyTip.yValueName = (...args: string[]): any => {
         if (!args.length) {
-            return yValueName as GetSetReturn<T, string, NearbyTip>;
+            return yValueName;
         }
         yValueName = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.altDataWithScale = <T extends any[] | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, any[], NearbyTip> => {
+    nearbyTip.altDataWithScale = (...args: AltDataWithScale[]): any => {
         if (!args.length) {
-            return altDataWithScale as GetSetReturn<T, any[], NearbyTip>;
+            return altDataWithScale;
         }
         altDataWithScale = args[0];
         return nearbyTip;
     };
 
-    nearbyTip.settings = <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Settings, NearbyTip> => {
+    nearbyTip.settings = (...args: Settings[]): any => {
         if (!args.length) {
-            return base.settings() as unknown as GetSetReturn<
-                T,
-                Settings,
-                NearbyTip
-            >;
+            return base.settings();
         }
         base.settings(args[0]);
         return nearbyTip;
     };
 
     fc.rebindAll(nearbyTip, base);
-    return nearbyTip;
+    return nearbyTip as NearbyTip;
 };
diff --git a/packages/perspective-viewer-d3fc/src/ts/tooltip/tooltip.ts b/packages/perspective-viewer-d3fc/src/ts/tooltip/tooltip.ts
index 10c493894a..bc7778b383 100644
--- a/packages/perspective-viewer-d3fc/src/ts/tooltip/tooltip.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/tooltip/tooltip.ts
@@ -16,19 +16,19 @@ import { getOrCreateElement, isElementOverflowing } from "../utils/utils";
 import tooltipTemplate from "../../html/tooltip.html";
 import { generateHtml } from "./generateHTML";
 import { selectionEvent } from "./selectionEvent";
-import { GetSetReturn, Settings } from "../types";
+import { Settings } from "../types";
 
 export interface ToolTip {
     (selection: any): void; // double check the return value is void.
-    alwaysShow: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, ToolTip>;
-    centered: <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, boolean, ToolTip>;
-    settings: <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Settings, ToolTip>;
+
+    alwaysShow(): boolean;
+    alwaysShow(alwaysShow: boolean): ToolTip;
+
+    centered(): boolean;
+    centered(centered: boolean): ToolTip;
+
+    settings(): Settings;
+    settings(settings: Settings): ToolTip;
 }
 
 export const tooltip = (): ToolTip => {
@@ -73,31 +73,25 @@ export const tooltip = (): ToolTip => {
         }
     };
 
-    _tooltip.alwaysShow = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, ToolTip> => {
+    _tooltip.alwaysShow = (...args: boolean[]): any => {
         if (!args.length) {
-            return alwaysShow as GetSetReturn<T, boolean, ToolTip>;
+            return alwaysShow;
         }
         alwaysShow = args[0];
         return _tooltip;
     };
 
-    _tooltip.centered = <T extends boolean | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, boolean, ToolTip> => {
+    _tooltip.centered = (...args: boolean[]): any => {
         if (!args.length) {
-            return centered as GetSetReturn<T, boolean, ToolTip>;
+            return centered;
         }
         centered = args[0];
         return _tooltip;
     };
 
-    _tooltip.settings = <T extends Settings | undefined = undefined>(
-        ...args: T[]
-    ): GetSetReturn<T, Settings, ToolTip> => {
+    _tooltip.settings = (...args: Settings[]): any => {
         if (!args.length) {
-            return settings as GetSetReturn<T, Settings, ToolTip>;
+            return settings;
         }
         settings = args[0];
         return _tooltip;
diff --git a/packages/perspective-viewer-d3fc/src/ts/types.ts b/packages/perspective-viewer-d3fc/src/ts/types.ts
index 87ffb78fad..6fe8aa96fd 100644
--- a/packages/perspective-viewer-d3fc/src/ts/types.ts
+++ b/packages/perspective-viewer-d3fc/src/ts/types.ts
@@ -37,20 +37,14 @@ export interface Chart {
 export type PadUnit = "percent" | "domain";
 export type Pad = [number, number];
 
-export type GetSetReturn<T, Arg, Func> = T extends undefined
-    ? Arg
-    : T extends Arg
-    ? Func
-    : never;
-
 export interface PaddingStrategy {
     (extent: any): any;
-    pad: <T extends Pad | undefined = undefined>(
-        nextPad?: T
-    ) => GetSetReturn<T, Pad, PaddingStrategy>;
-    padUnit: <T extends PadUnit | undefined = undefined>(
-        nextPadUnit?: T
-    ) => GetSetReturn<T, PadUnit, PaddingStrategy>;
+
+    pad(): Pad;
+    pad(nextPad: Pad): this;
+
+    padUnit(): PadUnit;
+    padUnit(nextPadUnit: PadUnit): this;
 }
 
 export type Axis = [number, number];
@@ -86,8 +80,6 @@ export type TreemapValue = {
     treemapRoute?: any[]; // string[]?
 };
 
-// Are these a particular type of settings?
-// Question: Is there a better type def for this?
 export type Settings = {
     hideKeys?: any[];
     agg_paths?: any; // any[]?
@@ -103,6 +95,7 @@ export type Settings = {
     splitValues: any[];
     textStyles: TextStyles;
     sunburstLevel?: any;
+    columns?: Record<string, Record<string, any>>; // Need to confirm this type.
     treemaps?: Record<string, TreemapValue>;
 };
 
@@ -119,21 +112,21 @@ export type ValueName =
 
 export interface Domain {
     (data: any[]): any;
-    valueName: <T extends ValueName | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName, Domain>;
-    valueNames: <T extends ValueName[] | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, ValueName[], Domain>;
-    orient?: <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Orientation, Domain>;
-    pad: <T extends Pad | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Pad, Domain>;
-    padUnit: <T extends PadUnit | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, PadUnit, Domain>;
+
+    valueName(): ValueName;
+    valueName(nextValueName: ValueName): this;
+
+    valueNames(): ValueName[];
+    valueNames(nextValueNames: ValueName[]): this;
+
+    orient(): Orientation;
+    orient(nextOrient: Orientation): this;
+
+    pad(): Pad;
+    pad(nextPad: Pad): this;
+
+    padUnit(): PadUnit;
+    padUnit(nextPadUnit: PadUnit): this;
 }
 
 export type DomainTuple = [number, number];
@@ -150,17 +143,14 @@ export interface ComponentData {
 export interface Component {
     (): ComponentData;
 
-    domain: <T extends Domain | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Domain, Component>;
+    domain(): Domain;
+    domain(nextDomain: Domain): this;
 
-    orient: <T extends Orientation | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, Orientation, Component>;
+    orient(): Orientation;
+    orient(nextOrient: Orientation): this;
 
-    settingName: <T extends SettingNameValues | undefined = undefined>(
-        ...args: T[]
-    ) => GetSetReturn<T, SettingNameValues, Component>;
+    settingName(): SettingNameValues;
+    settingName(nextSettingName: SettingNameValues): this;
 }
 
 export interface ScaleSequential extends d3.ScaleSequential<string> {