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export class Dispatcher {
  private constructor() { }
  public static instance = new Dispatcher()
  private events: object = {}

  public addEventListener(type: string, listener: Function) {
    const listeners = this.events[type] || []
    listeners.push(listener)
    this.events[type] = listeners
  }

  public removeEventListener(type: string, listener: Function) {
    const listeners = this.events[type] || []
    const index = listeners.indexOf(listener)
    listeners.splice(index, 1)
  }

  public dispatch(type: string, message: any) {
    const listeners = this.events[type] || []
    for (const listener of listeners) {
      listener(message)
    }
  }
}

精简版(js)：

const Eve = {
  events: {},
  on(type, listener) {
    const listeners = this.events[type] || []
    listeners.push(listener)
    this.events[type] = listeners
  },
  off(type, listener) {
    const listeners = this.events[type] || []
    const index = listeners.indexOf(listener)
    listeners.splice(index, 1)
  },
  emit(type, message) {
    const listeners = this.events[type] || []
    // 这里看情况，事件列表太长就不要slice
    for (const listener of listeners.slice()) {
      listener(message)
    }
  }
}

OnceDispatcher:

export class OnceDispatcher {
  private constructor() {}
  public static instance = new OnceDispatcher();
  private events: object = {};

  private routerParams = {} as any;
  setRouterParams(k: string, v: any) {
    this.routerParams[k] = v;
  }
  getRouterParams(k: string) {
    return this.routerParams[k];
  }

  public addEventListener(type: string, listener: Function) {
    this.events[type] = listener;
  }

  public removeEventListener(type: string) {
    delete this.events[type];
  }

  public dispatch(type: string, message: any) {
    const listener = this.events[type];
    if (typeof listener === 'function') {
      listener(message);
    }
  }
}