Resolve PR comments

Author: dwyfrequency

.changeset/silly-panthers-mix.md

@@ -2,4 +2,4 @@
 '@firebase/analytics': minor
 ---
 
-Add function setDefaultEventParameters() to set data that will be logged on every analytics SDK event
+Add function `setDefaultEventParameters()` to set data that will be logged on every analytics SDK event

packages/analytics/src/api.ts

@@ -227,10 +227,10 @@ export function setAnalyticsCollectionEnabled(
 }
 
 /**
- * Adds data that will be set on every event logged from the SDK, including automatic one.
- * By using gtag's set command, the values passed persist on the current page and are passed with
+ * Adds data that will be set on every event logged from the SDK, including automatic ones.
+ * By using gtag's "set" command, the values passed persist on the current page and are passed with
  * all subsequent events.
- *
+ * @public
  * @param customParams Any custom params the user may pass to gtag.js.
  */
 export function setDefaultEventParameters(customParams: CustomParams): void {

packages/analytics/src/functions.test.ts

@@ -180,7 +180,7 @@ describe('FirebaseAnalytics methods', () => {
     _setDefaultEventParametersForInit(eventParametersForInit);
     expect(defaultEventParametersForInit).to.deep.equal(eventParametersForInit);
   });
-  it('_setDefaultEventParametersForInit() adds new params correctly', async () => {
+  it('_setDefaultEventParametersForInit() replaces previous params with new params', async () => {
     const eventParametersForInit = {
       'github_user': 'dwyfrequency',
       'company': 'google'
@@ -189,7 +189,6 @@ describe('FirebaseAnalytics methods', () => {
     _setDefaultEventParametersForInit(eventParametersForInit);
     _setDefaultEventParametersForInit(additionalParams);
     expect(defaultEventParametersForInit).to.deep.equal({
-      ...eventParametersForInit,
       ...additionalParams
     });
   });

packages/analytics/src/functions.ts

@@ -150,20 +150,13 @@ export async function setAnalyticsCollectionEnabled(
 }
 
 /**
- * Sets the variable {@link defaultEventParametersForInit} for use in the initialization of
+ * Sets the variable `defaultEventParametersForInit` for use in the initialization of
  * analytics.
  *
  * @param customParams Any custom params the user may pass to gtag.js.
  */
 export function _setDefaultEventParametersForInit(
-  customParams: CustomParams
+  customParams?: CustomParams
 ): void {
-  if (defaultEventParametersForInit) {
-    defaultEventParametersForInit = {
-      ...defaultEventParametersForInit,
-      ...customParams
-    };
-  } else {
-    defaultEventParametersForInit = customParams;
-  }
+  defaultEventParametersForInit = customParams;
 }

packages/analytics/src/initialize-analytics.test.ts

@@ -30,6 +30,7 @@ import { Deferred } from '@firebase/util';
 import { _FirebaseInstallationsInternal } from '@firebase/installations';
 import { removeGtagScript } from '../testing/gtag-script-util';
 import { setDefaultEventParameters } from './api';
+import { defaultEventParametersForInit } from './functions';
 
 const fakeMeasurementId = 'abcd-efgh-ijkl';
 const fakeFid = 'fid-1234-zyxw';
@@ -100,11 +101,11 @@ describe('initializeAnalytics()', () => {
   });
   it('calls gtag set if there are default event parameters', async () => {
     stubFetch();
-    const defaultEventParametersForInit = {
+    const eventParametersForInit = {
       'github_user': 'dwyfrequency',
       'company': 'google'
     };
-    setDefaultEventParameters(defaultEventParametersForInit);
+    setDefaultEventParameters(eventParametersForInit);
     await _initializeAnalytics(
       app,
       dynamicPromisesList,
@@ -113,10 +114,9 @@ describe('initializeAnalytics()', () => {
       gtagStub,
       'dataLayer'
     );
-    expect(gtagStub).to.be.calledWith(
-      GtagCommand.SET,
-      defaultEventParametersForInit
-    );
+    expect(gtagStub).to.be.calledWith(GtagCommand.SET, eventParametersForInit);
+    // defaultEventParametersForInit is reset after initialization.
+    expect(defaultEventParametersForInit).to.equal(undefined);
   });
   it('puts dynamic fetch promise into dynamic promises list', async () => {
     stubFetch();

packages/analytics/src/initialize-analytics.ts

@@ -28,7 +28,10 @@ import {
 import { ERROR_FACTORY, AnalyticsError } from './errors';
 import { findGtagScriptOnPage, insertScriptTag } from './helpers';
 import { AnalyticsSettings } from './public-types';
-import { defaultEventParametersForInit } from './functions';
+import {
+  defaultEventParametersForInit,
+  _setDefaultEventParametersForInit
+} from './functions';
 
 async function validateIndexedDB(): Promise<boolean> {
   if (!isIndexedDBAvailable()) {
@@ -145,6 +148,7 @@ export async function _initializeAnalytics(
   // Detects if there is data that will be set on every event logged from the SDK.
   if (defaultEventParametersForInit) {
     gtagCore(GtagCommand.SET, defaultEventParametersForInit);
+    _setDefaultEventParametersForInit(undefined);
   }
 
   return dynamicConfig.measurementId;