Improve

src/app/store/chat-message.service.spec.ts

@@ -0,0 +1,16 @@
+import { TestBed } from '@angular/core/testing';
+
+import { ChatMessageService } from './chat-message.service';
+
+describe('ChatMessageService', () => {
+  let service: ChatMessageService;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({});
+    service = TestBed.inject(ChatMessageService);
+  });
+
+  it('should be created', () => {
+    expect(service).toBeTruthy();
+  });
+});

src/app/store/chat-message.service.ts

@@ -0,0 +1,42 @@
+import { Injectable } from '@angular/core';
+import { localstoreService } from './localstore.service'
+import { SHA1 }  from  'crypto-js'
+
+@Injectable({
+  providedIn: 'root'
+})
+export class ChatMessageService {
+
+  private _message = [] 
+  // local storage keyName
+  private keyName: string;
+
+  constructor() {
+
+    this.keyName = (SHA1(this.constructor.name)).toString()
+
+    setTimeout(()=> {
+      let restore = localstoreService.get(this.keyName, {})
+      this._message = restore.message || {}
+    }, 10)
+
+  }
+
+  getMessages(roomId) {
+    return this._message[roomId] || []
+  }
+
+  add(roomId, message) {
+    this._message[roomId] = message
+
+    setTimeout(()=> {
+      localstoreService.set(this.keyName, {
+        message: this._message
+      })
+    }, 5000)
+  }
+
+}
+
+
+export const ChatMessageStore = new ChatMessageService()