Fix timestamps when metrics are submitted synchronously with date

package.json

@@ -1,6 +1,6 @@
 {
   "name": "datadog-lambda-js",
-  "version": "2.20.0",
+  "version": "2.21.0",
   "description": "Lambda client library that supports hybrid tracing in node js",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/metrics/batcher.spec.ts

@@ -4,7 +4,7 @@ import { Distribution } from "./model";
 describe("Batcher", () => {
   it("joins metrics with different tag orders", () => {
     const batcher = new Batcher();
-    const timestamp = new Date(1559928315);
+    const timestamp = new Date(1559928315000);
     const distribution1 = new Distribution(
       "my-dist",
       [{ timestamp, value: 1 }, { timestamp, value: 2 }],
@@ -29,7 +29,7 @@ describe("Batcher", () => {
 
   it("doesn't join metrics with different tags", () => {
     const batcher = new Batcher();
-    const timestamp = new Date(1559928315);
+    const timestamp = new Date(1559928315000);
     const distribution1 = new Distribution(
       "my-dist",
       [{ timestamp, value: 1 }, { timestamp, value: 2 }],

src/metrics/model.spec.ts

@@ -2,7 +2,7 @@ import { Distribution } from "./model";
 
 describe("Distribution", () => {
   it("converts to a APIMetric", () => {
-    const timestamp = new Date(1559928315);
+    const timestamp = new Date(1559928315000);
 
     const distribution = new Distribution(
       "my-dist",

src/metrics/model.ts

@@ -42,7 +42,9 @@ export class Distribution implements Metric {
 
   public toAPIMetrics(): APIMetric[] {
     const points: APIPoint[] = this.points.map((point) => {
-      return [point.timestamp.getTime(), [point.value]];
+      // Convert the milliseconds we get from getTime to seconds for the Datadog API
+      const unixSeconds = Math.floor(point.timestamp.getTime() / 1000);
+      return [unixSeconds, [point.value]];
     });
     return [
       {

src/metrics/processor.spec.ts

@@ -22,7 +22,7 @@ class MockAPIClient implements Client {
 }
 
 function makeMetric(name: string = "my-metric", value: number = 1): Metric {
-  const timestamp = new Date(1559941498);
+  const timestamp = new Date(1559941498000);
   return new Distribution(name, [{ timestamp, value }], "tag:a", "tag:b");
 }