fix(core): only try to retrieve transferred state on the browser (#50144)

alan-agius4 · alxhub · commit 346ab73dd95f · 2023-05-08T14:36:13.000-07:00
Prior to this commit we tried to retrieve transferred state on both browser and server. Doing this on the server was redundant and could causes issues as `document` might be undefined. Closes #50138 PR Close #50144
diff --git a/packages/core/src/transfer_state.ts b/packages/core/src/transfer_state.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {APP_ID} from './application_tokens';
+import {APP_ID, PLATFORM_ID} from './application_tokens';
 import {inject} from './di/injector_compatibility';
 import {ɵɵdefineInjectable} from './di/interface/defs';
 import {getDocument} from './render3/interfaces/document';
@@ -72,7 +72,10 @@ export function makeStateKey<T = void>(key: string): StateKey<T> {
 
 function initTransferState() {
   const transferState = new TransferState();
-  transferState.store = retrieveTransferredState(getDocument(), inject(APP_ID));
+  if (inject(PLATFORM_ID) === 'browser') {
+    transferState.store = retrieveTransferredState(getDocument(), inject(APP_ID));
+  }
+
   return transferState;
 }
 
@@ -101,7 +104,7 @@ export class TransferState {
       });
 
   /** @internal */
-  store: {[k: string]: unknown|undefined} = {};
+  store: Record<string, unknown|undefined> = {};
 
   private onSerializeCallbacks: {[k: string]: () => unknown | undefined} = {};
 
@@ -165,18 +168,18 @@ export class TransferState {
   }
 }
 
-function retrieveTransferredState(doc: Document, appId: string) {
+function retrieveTransferredState(doc: Document, appId: string): Record<string, unknown|undefined> {
   // Locate the script tag with the JSON data transferred from the server.
   // The id of the script tag is set to the Angular appId + 'state'.
   const script = doc.getElementById(appId + '-state');
-  let initialState = {};
-  if (script && script.textContent) {
+  if (script?.textContent) {
     try {
       // Avoid using any here as it triggers lint errors in google3 (any is not allowed).
-      initialState = JSON.parse(unescapeTransferStateContent(script.textContent)) as {};
+      return JSON.parse(unescapeTransferStateContent(script.textContent)) as {};
     } catch (e) {
       console.warn('Exception while restoring TransferState for app ' + appId, e);
     }
   }
-  return initialState;
+
+  return {};
 }
diff --git a/packages/core/test/transfer_state_spec.ts b/packages/core/test/transfer_state_spec.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {APP_ID as APP_ID_TOKEN} from '@angular/core';
+import {APP_ID as APP_ID_TOKEN, PLATFORM_ID} from '@angular/core';
 import {TestBed} from '@angular/core/testing';
 
 import {getDocument} from '../src/render3/interfaces/document';
@@ -44,7 +44,8 @@ describe('TransferState', () => {
   beforeEach(() => {
     doc = getDocument();
     TestBed.configureTestingModule({
-      providers: [{provide: APP_ID_TOKEN, useValue: APP_ID}],
+      providers:
+          [{provide: APP_ID_TOKEN, useValue: APP_ID}, {provide: PLATFORM_ID, useValue: 'browser'}],
     });
   });
 
