🔊 Add feature flags to telemetry events

packages/core/src/domain/configuration/experimentalFeatures.ts

@@ -5,7 +5,7 @@
  * So keep in mind that in certain configurations, your experimental feature flag may affect other products.
  */
 
-let enabledExperimentalFeatures: Set<string>
+let enabledExperimentalFeatures: Set<string> | undefined
 
 export function updateExperimentalFeatures(enabledFeatures: string[] | undefined): void {
   // Safely handle external data
@@ -20,7 +20,7 @@ export function updateExperimentalFeatures(enabledFeatures: string[] | undefined
   enabledFeatures
     .filter((flag) => typeof flag === 'string')
     .forEach((flag: string) => {
-      enabledExperimentalFeatures.add(flag)
+      enabledExperimentalFeatures!.add(flag)
     })
 }
 
@@ -31,3 +31,7 @@ export function isExperimentalFeatureEnabled(featureName: string): boolean {
 export function resetExperimentalFeatures(): void {
   enabledExperimentalFeatures = new Set()
 }
+
+export function getExperimentalFeatures(): Set<string> {
+  return enabledExperimentalFeatures || new Set()
+}

packages/core/src/domain/configuration/index.ts

@@ -10,5 +10,6 @@ export {
   isExperimentalFeatureEnabled,
   updateExperimentalFeatures,
   resetExperimentalFeatures,
+  getExperimentalFeatures,
 } from './experimentalFeatures'
 export * from './intakeSites'

packages/core/src/domain/telemetry/telemetry.spec.ts

@@ -1,7 +1,7 @@
 import type { StackTrace } from '@datadog/browser-core'
 import { callMonitored } from '../../tools/monitor'
 import type { Configuration } from '../configuration'
-import { INTAKE_SITE_US1, INTAKE_SITE_US1_FED } from '../configuration'
+import { updateExperimentalFeatures, INTAKE_SITE_US1, INTAKE_SITE_US1_FED } from '../configuration'
 import { resetTelemetry, startTelemetry, scrubCustomerFrames, formatError } from './telemetry'
 
 function startAndSpyTelemetry(configuration?: Partial<Configuration>) {
@@ -31,6 +31,16 @@ describe('telemetry', () => {
     expect(notifySpy).toHaveBeenCalledTimes(1)
   })
 
+  it('should contains feature flags', () => {
+    updateExperimentalFeatures(['foo'])
+    const { notifySpy } = startAndSpyTelemetry()
+    callMonitored(() => {
+      throw new Error('message')
+    })
+
+    expect(notifySpy.calls.mostRecent().args[0].experimental_features).toEqual(['foo'])
+  })
+
   describe('telemetry context', () => {
     it('should be added to telemetry events', () => {
       const { telemetry, notifySpy } = startAndSpyTelemetry()

packages/core/src/domain/telemetry/telemetry.ts

@@ -1,9 +1,9 @@
 import type { Context } from '../../tools/context'
 import { ConsoleApiName } from '../../tools/display'
 import { toStackTraceString } from '../../tools/error'
-import { assign, combine, jsonStringify, performDraw, includes, startsWith } from '../../tools/utils'
+import { assign, combine, jsonStringify, performDraw, includes, startsWith, arrayFrom } from '../../tools/utils'
 import type { Configuration } from '../configuration'
-import { INTAKE_SITE_STAGING, INTAKE_SITE_US1_FED } from '../configuration'
+import { getExperimentalFeatures, INTAKE_SITE_STAGING, INTAKE_SITE_US1_FED } from '../configuration'
 import type { StackTrace } from '../tracekit'
 import { computeStackTrace } from '../tracekit'
 import { Observable } from '../../tools/observable'
@@ -80,6 +80,7 @@ export function startTelemetry(configuration: Configuration): Telemetry {
           format_version: 2 as const,
         },
         telemetry: event as any, // https://github.com/microsoft/TypeScript/issues/48457
+        experimental_features: arrayFrom(getExperimentalFeatures()),
       },
       contextProvider !== undefined ? contextProvider() : {}
     )

packages/core/src/tools/utils.spec.ts

@@ -1,6 +1,7 @@
 import type { Clock } from '../../test/specHelper'
 import { mockClock } from '../../test/specHelper'
 import {
+  arrayFrom,
   combine,
   cssEscape,
   deepClone,
@@ -594,3 +595,19 @@ describe('elementMatches', () => {
     expect(elementMatches(element, '.foo')).toEqual(false)
   })
 })
+
+describe('arrayFrom', () => {
+  it('should return an array from a Set', () => {
+    const set = new Set()
+    set.add('foo')
+
+    expect(arrayFrom(set)).toEqual(['foo'])
+  })
+
+  it('should return an array from a array like object', () => {
+    const div = document.createElement('div')
+    div.classList.add('foo')
+
+    expect(arrayFrom(div.classList)).toEqual(['foo'])
+  })
+})

packages/core/src/tools/utils.ts

@@ -209,11 +209,21 @@ export function includes(candidate: string | unknown[], search: any) {
   return candidate.indexOf(search) !== -1
 }
 
-export function arrayFrom<T>(arrayLike: ArrayLike<T>): T[] {
+export function arrayFrom<T>(arrayLike: ArrayLike<T> | Set<T>): T[] {
+  if (Array.from) {
+    return Array.from(arrayLike)
+  }
+
   const array = []
-  for (let i = 0; i < arrayLike.length; i++) {
-    array.push(arrayLike[i])
+
+  if (arrayLike instanceof Set) {
+    arrayLike.forEach((item) => array.push(item))
+  } else {
+    for (let i = 0; i < arrayLike.length; i++) {
+      array.push(arrayLike[i])
+    }
   }
+
   return array
 }