client/src/app/app.service.ts

   1 import { Injectable } from '@angular/core';
   2
   3 export type InternalStateType = {
   4   [key: string]: any
   5 };
   6
   7 @Injectable()
   8 export class AppState {
   9
  10   public _state: InternalStateType = { };
  11
  12   /**
  13    * Already return a clone of the current state.
  14    */
  15   public get state() {
  16     return this._state = this._clone(this._state);
  17   }
  18   /**
  19    * Never allow mutation
  20    */
  21   public set state(value) {
  22     throw new Error('do not mutate the `.state` directly');
  23   }
  24
  25   public get(prop?: any) {
  26     /**
  27      * Use our state getter for the clone.
  28      */
  29     const state = this.state;
  30     return state.hasOwnProperty(prop) ? state[prop] : state;
  31   }
  32
  33   public set(prop: string, value: any) {
  34     /**
  35      * Internally mutate our state.
  36      */
  37     return this._state[prop] = value;
  38   }
  39
  40   private _clone(object: InternalStateType) {
  41     /**
  42      * Simple object clone.
  43      */
  44     return JSON.parse(JSON.stringify( object ));
  45   }
  46 }