Add updateCDNSettings() option (#870)

.changeset/polite-bottles-smell.md

@@ -0,0 +1,5 @@
+---
+'@segment/analytics-next': minor
+---
+
+Add updateCDNSettings option

packages/browser/src/browser/__tests__/update-cdn-settings.test.ts

@@ -0,0 +1,70 @@
+import { AnalyticsBrowser } from '../..'
+import { setGlobalCDNUrl } from '../../lib/parse-cdn'
+import { remoteLoader } from '../../plugins/remote-loader'
+import unfetch from 'unfetch'
+import { createSuccess } from '../../test-helpers/factories'
+jest.mock('unfetch')
+
+const INTG_TO_DELETE = 'deleteMe'
+
+const cdnSettings = {
+  integrations: {
+    [INTG_TO_DELETE]: { bar: true },
+    otherIntegration: { foo: true },
+  },
+}
+const mockFetchSettingsSuccessResponse = (cdnSettings: any) => {
+  return jest
+    .mocked(unfetch)
+    .mockImplementation(() => createSuccess(cdnSettings))
+}
+
+jest.mock('../../plugins/remote-loader')
+const remoteLoaderSpy = jest.fn().mockResolvedValue([])
+jest.mocked(remoteLoader).mockImplementation(remoteLoaderSpy)
+
+describe('updateCDNSettings configuration option', () => {
+  beforeEach(() => {
+    setGlobalCDNUrl(undefined as any)
+    ;(window as any).analytics = undefined
+  })
+  it('should update the configuration options if they are passed directly', async () => {
+    await AnalyticsBrowser.load(
+      {
+        writeKey: 'foo',
+        cdnSettings,
+      },
+      {
+        updateCDNSettings: (settings) => {
+          delete settings.integrations.deleteMe
+          return settings
+        },
+      }
+    )
+    const [arg1] = remoteLoaderSpy.mock.lastCall
+    expect(arg1.integrations.otherIntegration).toEqual(
+      cdnSettings.integrations.otherIntegration
+    )
+    expect(arg1.integrations[INTG_TO_DELETE]).toBeUndefined()
+  })
+
+  it('should update the configuration options if they are fetched', async () => {
+    mockFetchSettingsSuccessResponse(cdnSettings)
+    await AnalyticsBrowser.load(
+      {
+        writeKey: 'foo',
+      },
+      {
+        updateCDNSettings: (settings) => {
+          delete settings.integrations.deleteMe
+          return settings
+        },
+      }
+    )
+    const [arg1] = remoteLoaderSpy.mock.lastCall
+    expect(arg1.integrations.otherIntegration).toEqual(
+      cdnSettings.integrations.otherIntegration
+    )
+    expect(arg1.integrations[INTG_TO_DELETE]).toBeUndefined()
+  })
+})

packages/browser/src/browser/index.ts

@@ -268,10 +268,14 @@ async function loadAnalytics(
   // this is an ugly side-effect, but it's for the benefits of the plugins that get their cdn via getCDN()
   if (settings.cdnURL) setGlobalCDNUrl(settings.cdnURL)
 
-  const legacySettings =
+  let legacySettings =
     settings.cdnSettings ??
     (await loadLegacySettings(settings.writeKey, settings.cdnURL))
 
+  if (options.updateCDNSettings) {
+    legacySettings = options.updateCDNSettings(legacySettings)
+  }
+
   const retryQueue: boolean =
     legacySettings.integrations['Segment.io']?.retryQueue ?? true
 

packages/browser/src/core/analytics/index.ts

@@ -49,6 +49,7 @@ import { PriorityQueue } from '../../lib/priority-queue'
 import { getGlobal } from '../../lib/get-global'
 import { AnalyticsClassic, AnalyticsCore } from './interfaces'
 import { HighEntropyHint } from '../../lib/client-hints/interfaces'
+import type { LegacySettings } from '../../browser'
 
 const deprecationWarning =
   'This is being deprecated and will be not be available in future releases of Analytics JS'
@@ -98,6 +99,11 @@ export interface InitOptions {
   plan?: Plan
   retryQueue?: boolean
   obfuscate?: boolean
+  /**
+   * This callback allows you to update/mutate CDN Settings.
+   * This is called directly after settings are fetched from the CDN.
+   */
+  updateCDNSettings?: (settings: LegacySettings) => LegacySettings
   /**
    * Disables or sets constraints on processing of query string parameters
    */