fix(tracker): prevent initializing Matomo more than once

Cherry-picked from 784b1de

Author: EmmanuelRoux

projects/tracker/src/lib/errors.ts

@@ -1 +1,2 @@
 export const ALREADY_INJECTED_ERROR = 'Matomo trackers have already been initialized';
+export const ALREADY_INITIALIZED_ERROR = 'Matomo has already been initialized';

projects/tracker/src/lib/matomo-initializer.service.spec.ts

@@ -8,7 +8,7 @@ import {
   MatomoConsentMode,
   MatomoInitializationMode,
 } from './configuration';
-import { ALREADY_INJECTED_ERROR } from './errors';
+import { ALREADY_INITIALIZED_ERROR, ALREADY_INJECTED_ERROR } from './errors';
 import { MatomoHolder } from './holder';
 import { MatomoInitializerService } from './matomo-initializer.service';
 import { MatomoTracker, NoopMatomoTracker } from './matomo-tracker.service';
@@ -487,6 +487,22 @@ describe('MatomoInitializerService', () => {
     expect(tracker.setSiteId).toHaveBeenCalledOnceWith('fakeSiteId');
   });
 
+  it('should map deprecated init() method to initialize()', () => {
+    // Given
+    const service = instantiate({
+      trackerUrl: '',
+      siteId: '',
+    });
+
+    spyOn(service, 'initialize');
+
+    // When
+    service.init();
+
+    // Then
+    expect(service.initialize).toHaveBeenCalledOnceWith();
+  });
+
   it('should throw an error when initialized trackers more than once', () => {
     // Given
     const service = instantiate({
@@ -502,19 +518,17 @@ describe('MatomoInitializerService', () => {
     );
   });
 
-  it('should map deprecated init() method to initialize()', () => {
+  it('should throw an error when initialized more than once', () => {
     // Given
     const service = instantiate({
       trackerUrl: '',
       siteId: '',
     });
 
-    spyOn(service, 'initialize');
-
     // When
-    service.init();
+    service.initialize();
 
     // Then
-    expect(service.initialize).toHaveBeenCalledOnceWith();
+    expect(() => service.initialize()).toThrowError(ALREADY_INITIALIZED_ERROR);
   });
 });

projects/tracker/src/lib/matomo-initializer.service.ts

@@ -13,7 +13,7 @@ import {
   MatomoInitializationMode,
   MatomoTrackerConfiguration,
 } from './configuration';
-import { ALREADY_INJECTED_ERROR } from './errors';
+import { ALREADY_INITIALIZED_ERROR, ALREADY_INJECTED_ERROR } from './errors';
 import { initializeMatomoHolder } from './holder';
 import { MatomoTracker } from './matomo-tracker.service';
 import { MATOMO_SCRIPT_FACTORY, MatomoScriptFactory } from './script-factory';
@@ -76,6 +76,7 @@ export class NoopMatomoInitializer
   ],
 })
 export class MatomoInitializerService {
+  private initialized = false;
   private injected = false;
 
   constructor(
@@ -95,9 +96,15 @@ export class MatomoInitializerService {
   initialize(): void {
     this.runPreInitTasks();
 
+    if (this.initialized) {
+      throw new Error(ALREADY_INITIALIZED_ERROR);
+    }
+
     if (isAutoConfigurationMode(this.config)) {
       this.injectMatomoScript(this.config);
     }
+
+    this.initialized = true;
   }
 
   initializeTracker(config: AutoMatomoConfiguration<MatomoInitializationMode.AUTO_DEFERRED>): void {