diff --git a/src/plugins/data/public/search/aggs/buckets/date_histogram.ts b/src/plugins/data/public/search/aggs/buckets/date_histogram.ts
index f00b63836679d7..0c222bbf7cc120 100644
--- a/src/plugins/data/public/search/aggs/buckets/date_histogram.ts
+++ b/src/plugins/data/public/search/aggs/buckets/date_histogram.ts
@@ -44,9 +44,11 @@ const updateTimeBuckets = (
   timefilter: TimefilterContract,
   customBuckets?: IBucketDateHistogramAggConfig['buckets']
 ) => {
-  const bounds = agg.params.timeRange ? timefilter.calculateBounds(agg.params.timeRange) : null;
+  const bounds = agg.params.timeRange
+    ? timefilter.calculateBounds(agg.params.timeRange)
+    : undefined;
   const buckets = customBuckets || agg.buckets;
-  buckets.setBounds(agg.fieldIsTimeField() ? bounds : null);
+  buckets.setBounds(agg.fieldIsTimeField() ? bounds : undefined);
   buckets.setInterval(agg.params.interval);
 };
 
diff --git a/src/plugins/data/public/search/aggs/buckets/lib/time_buckets/time_buckets.ts b/src/plugins/data/public/search/aggs/buckets/lib/time_buckets/time_buckets.ts
index ce918201582d00..fb593c874a644b 100644
--- a/src/plugins/data/public/search/aggs/buckets/lib/time_buckets/time_buckets.ts
+++ b/src/plugins/data/public/search/aggs/buckets/lib/time_buckets/time_buckets.ts
@@ -18,7 +18,7 @@
  */
 
 import _ from 'lodash';
-import moment from 'moment';
+import moment, { Moment } from 'moment';
 
 import { IUiSettingsClient } from 'src/core/public';
 import { parseInterval } from '../../../../../../common';
@@ -194,7 +194,7 @@ export class TimeBuckets {
    *
    * @returns {undefined}
    */
-  setBounds(input?: null | TimeRangeBounds | TimeRangeBounds[]) {
+  setBounds(input?: TimeRangeBounds | TimeRangeBounds[]) {
     if (!input) return this.clearBounds();
 
     let bounds;
@@ -205,11 +205,9 @@ export class TimeBuckets {
       bounds = Array.isArray(input) ? input : [];
     }
 
-    const moments = _(bounds)
-      .map(_.ary(moment, 1))
-      .sortBy(Number);
+    const moments: Moment[] = _.sortBy(bounds, Number);
 
-    const valid = moments.size() === 2 && moments.every(isValidMoment);
+    const valid = moments.length === 2 && moments.every(isValidMoment);
     if (!valid) {
       this.clearBounds();
       throw new Error('invalid bounds set: ' + input);
diff --git a/src/plugins/visualizations/public/legacy/build_pipeline.ts b/src/plugins/visualizations/public/legacy/build_pipeline.ts
index 23919c62f5ecec..7961e3cfc89851 100644
--- a/src/plugins/visualizations/public/legacy/build_pipeline.ts
+++ b/src/plugins/visualizations/public/legacy/build_pipeline.ts
@@ -94,8 +94,10 @@ const getSchemas = (
   const createSchemaConfig = (accessor: number, agg: IAggConfig): SchemaConfig => {
     if (isDateHistogramBucketAggConfig(agg)) {
       agg.params.timeRange = timeRange;
-      const bounds = agg.params.timeRange ? timefilter.calculateBounds(agg.params.timeRange) : null;
-      agg.buckets.setBounds(agg.fieldIsTimeField() ? bounds : null);
+      const bounds = agg.params.timeRange
+        ? timefilter.calculateBounds(agg.params.timeRange)
+        : undefined;
+      agg.buckets.setBounds(agg.fieldIsTimeField() ? bounds : undefined);
       agg.buckets.setInterval(agg.params.interval);
     }