feat: add exponential histogram accumulation / aggregator

Author: mwear

CHANGELOG.md

@@ -11,6 +11,7 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :rocket: (Enhancement)
 
+* feat(sdk-metrics): add exponential histogram accumulation / aggregator [#3505](https://github.com/open-telemetry/opentelemetry-js/pull/3505) @mwear
 * feat(sdk-metrics): add exponential histogram mapping functions [#3504](https://github.com/open-telemetry/opentelemetry-js/pull/3504) @mwear
 
 ### :bug: (Bug Fix)

experimental/packages/otlp-transformer/src/metrics/internal.ts

@@ -19,6 +19,7 @@ import {
   AggregationTemporality,
   DataPoint,
   DataPointType,
+  ExponentialHistogram,
   Histogram,
   MetricData,
   ResourceMetrics,
@@ -96,7 +97,10 @@ export function toMetric(metricData: MetricData): IMetric {
 }
 
 function toSingularDataPoint(
-  dataPoint: DataPoint<number> | DataPoint<Histogram>,
+  dataPoint:
+    | DataPoint<number>
+    | DataPoint<Histogram>
+    | DataPoint<ExponentialHistogram>,
   valueType: ValueType
 ) {
   const out: INumberDataPoint = {