diff --git a/src/fill.ts b/src/fill.ts
index e20add2..7160d1b 100644
--- a/src/fill.ts
+++ b/src/fill.ts
@@ -1,10 +1,15 @@
 import { curry, difference, keys, reduce } from 'ramda'
 import { getObjectSchema } from './api'
-import { ObjectSchema, SchemaCollection, SchemaVersion } from './objects'
+import {
+  ObjectSchema,
+  PlainObject,
+  SchemaCollection,
+  SchemaVersion,
+} from './objects'
 
 // TODO: add types to input args
 export const fillBySchema = curry(
-  (schema: ObjectSchema, object: object): object => {
+  (schema: ObjectSchema, object: PlainObject): PlainObject => {
     // @ts-ignore
     schema = schema.properties || (schema.schema || schema.items).properties
     const objectProps = keys(object)
@@ -12,7 +17,7 @@ export const fillBySchema = curry(
 
     const missingProperties = difference(schemaProps, objectProps)
     const filledObject = reduce(
-      (result: object, key: string): object => {
+      (result: PlainObject, key: string): PlainObject => {
         const property = schema[key]
         if ('defaultValue' in property) {
           const value = property.defaultValue
@@ -27,7 +32,7 @@ export const fillBySchema = curry(
       missingProperties,
     )
 
-    return filledObject
+    return <PlainObject>filledObject
   },
 )
 
@@ -36,7 +41,7 @@ const fillObject = (
   schemaName: string,
   version: SchemaVersion,
   object: object,
-) => {
+): PlainObject => {
   const schema = getObjectSchema(schemas, schemaName, version)
   if (!schema) {
     throw new Error(
@@ -47,7 +52,7 @@ const fillObject = (
     throw new Error('Expected an object to trim')
   }
 
-  return fillBySchema(schema, object)
+  return fillBySchema(schema, <PlainObject>object)
 }
 
 /**
diff --git a/src/trim.ts b/src/trim.ts
index 6951475..e76a38b 100644
--- a/src/trim.ts
+++ b/src/trim.ts
@@ -1,41 +1,48 @@
 import { contains, curry, keys, map, reduce } from 'ramda'
 import { getObjectSchema } from './api'
-import { ObjectSchema, SchemaCollection, SchemaVersion } from './objects'
+import {
+  ObjectSchema,
+  PlainObject,
+  SchemaCollection,
+  SchemaVersion,
+} from './objects'
 import { hasPropertiesArray, isJsonSchema } from './sanitize'
 
 // TODO: add types to input args
 /**
  * Takes an object and removes all properties not listed in the schema
  */
-export const trimBySchema = curry((schema: ObjectSchema, object: object) => {
-  // @ts-ignore
-  schema = schema.properties || (schema.schema || schema.items).properties
-  const objectProps = keys(object)
-  const schemaProps = keys(schema)
-  return reduce(
-    (trimmedObj, prop) => {
-      if (contains(prop, schemaProps)) {
-        if (object[prop] && isJsonSchema(schema[prop])) {
-          trimmedObj[prop] = trimBySchema(schema[prop], object[prop])
-        } else if (object[prop] && hasPropertiesArray(schema[prop])) {
-          trimmedObj[prop] = map(trimBySchema(schema[prop]), object[prop])
-        } else {
-          trimmedObj[prop] = object[prop]
+export const trimBySchema = curry(
+  (schema: ObjectSchema, object: object): PlainObject => {
+    // @ts-ignore
+    schema = schema.properties || (schema.schema || schema.items).properties
+    const objectProps = keys(object)
+    const schemaProps = keys(schema)
+    return reduce(
+      (trimmedObj, prop) => {
+        if (contains(prop, schemaProps)) {
+          if (object[prop] && isJsonSchema(schema[prop])) {
+            trimmedObj[prop] = trimBySchema(schema[prop], object[prop])
+          } else if (object[prop] && hasPropertiesArray(schema[prop])) {
+            trimmedObj[prop] = map(trimBySchema(schema[prop]), object[prop])
+          } else {
+            trimmedObj[prop] = object[prop]
+          }
         }
-      }
-      return trimmedObj
-    },
-    {},
-    objectProps,
-  )
-})
+        return trimmedObj
+      },
+      {},
+      objectProps,
+    )
+  },
+)
 
 const trimObject = (
   schemas: SchemaCollection,
   schemaName: string,
   version: SchemaVersion,
-  object: object,
-) => {
+  object: PlainObject,
+): PlainObject => {
   const schema = getObjectSchema(schemas, schemaName, version)
   if (!schema) {
     throw new Error(
@@ -55,6 +62,6 @@ const trimObject = (
  * @example
  *    const o = ... // some object
  *    const t = trim('Person', '1.0.0', o)
- *    // t only has properties from the schema Person@1.0.0
+ *    // t only has properties from the schema Person v1.0.0
  */
 export const trim = curry(trimObject)