diff --git a/packages/apollo-engine-reporting-protobuf/src/reports.proto b/packages/apollo-engine-reporting-protobuf/src/reports.proto
index 0c6bc319d78..c2284cc480c 100644
--- a/packages/apollo-engine-reporting-protobuf/src/reports.proto
+++ b/packages/apollo-engine-reporting-protobuf/src/reports.proto
@@ -4,6 +4,12 @@ package mdg.engine.proto;
 
 import "google/protobuf/timestamp.proto";
 
+import "google/protobuf/descriptor.proto";
+
+extend google.protobuf.FieldOptions {
+	bool js_use_toArray = 50505;
+}
+
 message Trace {
 	message CachePolicy {
 		enum Scope {
@@ -284,16 +290,16 @@ message PathErrorStats {
 }
 
 message QueryLatencyStats {
-	repeated int64 latency_count = 1;
+	repeated int64 latency_count = 1 [(js_use_toArray)=true];
 	uint64 request_count = 2;
 	uint64 cache_hits = 3;
 	uint64 persisted_query_hits = 4;
 	uint64 persisted_query_misses = 5;
-	repeated int64 cache_latency_count = 6;
+	repeated int64 cache_latency_count = 6 [(js_use_toArray)=true];
 	PathErrorStats root_error_stats = 7;
 	uint64 requests_with_errors_count = 8;
-	repeated int64 public_cache_ttl_count = 9;
-	repeated int64 private_cache_ttl_count = 10;
+	repeated int64 public_cache_ttl_count = 9 [(js_use_toArray)=true];
+	repeated int64 private_cache_ttl_count = 10 [(js_use_toArray)=true];
 	uint64 registered_operation_count = 11;
 	uint64 forbidden_operation_count = 12;
 }
diff --git a/packages/apollo-engine-reporting/src/ContextualizedStats.ts b/packages/apollo-engine-reporting/src/ContextualizedStats.ts
index 1f5e7bbb191..1efdfdc882d 100644
--- a/packages/apollo-engine-reporting/src/ContextualizedStats.ts
+++ b/packages/apollo-engine-reporting/src/ContextualizedStats.ts
@@ -6,6 +6,8 @@ import {
   ContextualizedStats as ContextualizedStatsProto,
   ITypeStat as TypeStatProto,
   IFieldStat as FieldStatProto,
+  IQueryLatencyStats,
+  QueryLatencyStats,
 } from 'apollo-engine-reporting-protobuf';
 
 export interface FieldStat {
@@ -15,22 +17,6 @@ export interface FieldStat {
   requestsWithErrorsCount: number;
   latencyCount: DurationHistogram;
 }
-
-export interface QueryLatencyStats {
-  readonly latencyCount: DurationHistogram;
-  requestCount: number;
-  cacheHits: number;
-  persistedQueryHits: number;
-  persistedQueryMisses: number;
-  readonly cacheLatencyCount: DurationHistogram;
-  readonly rootErrorStats: IPathErrorStats;
-  requestsWithErrorCount: number;
-  readonly publicCacheTtlCount: DurationHistogram;
-  readonly privateCacheTtlCount: DurationHistogram;
-  registeredOperationCount: number;
-  forbiddenOperationCount: number;
-}
-
 export class ContextualizedStats {
   statsContext: IStatsContext;
   queryLatencyStats: QueryLatencyStats;
@@ -41,7 +27,7 @@ export class ContextualizedStats {
 
   constructor(statsContext: IStatsContext) {
     this.statsContext = statsContext;
-    this.queryLatencyStats = {
+    this.queryLatencyStats = new QueryLatencyStats({
       latencyCount: new DurationHistogram(),
       requestCount: 0,
       cacheHits: 0,
@@ -54,10 +40,11 @@ export class ContextualizedStats {
       privateCacheTtlCount: new DurationHistogram(),
       registeredOperationCount: 0,
       forbiddenOperationCount: 0,
-    };
+    });
   }
 
   public addTrace(trace: Trace) {
+
     const queryLatencyStats = this.queryLatencyStats;
     queryLatencyStats.requestCount++;
     if (trace.fullQueryCacheHit) {