Class Event

packages/shell/src/api/event.ts:13–84

const eventBusSymbol = Symbol('eventBus');

export class Event implements IPublicApiEvent {
  private readonly [eventBusSymbol]: IEventBus;
  private readonly options: EventOptions;

  constructor(eventBus: IEventBus, options: EventOptions, public workspaceMode = false) {
    this[eventBusSymbol] = eventBus;
    this.options = options;
    if (!this.options.prefix) {
      logger.warn('prefix is required while initializing Event');
    }
  }

  /**
   * 监听事件
   * @param event 事件名称
   * @param listener 事件回调
   */
  on(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable {
    if (isPluginEventName(event)) {
      return this[eventBusSymbol].on(event, listener);
    } else {
      logger.warn(`fail to monitor on event ${event}, event should have a prefix like 'somePrefix:eventName'`);
      return () => {};
    }
  }

  /**
   * 监听事件，会在其他回调函数之前执行
   * @param event 事件名称
   * @param listener 事件回调
   */
  prependListener(event: string, listener: (...args: any[]) => void): IPublicTypeDisposable {
    if (isPluginEventName(event)) {
      return this[eventBusSymbol].prependListener(event, listener);
    } else {
      logger.warn(`fail to prependListener event ${event}, event should have a prefix like 'somePrefix:eventName'`);
      return () => {};
    }
  }

  /**
   * 取消监听事件
   * @param event 事件名称
   * @param listener 事件回调
   */
  off(event: string, listener: (...args: any[]) => void) {
    this[eventBusSymbol].off(event, listener);
  }

  /**
   * 触发事件
   * @param event 事件名称
   * @param args 事件参数
   * @returns
   */
  emit(event: string, ...args: any[]) {
    if (!this.options.prefix) {
      logger.warn('Event#emit has been forbidden while prefix is not specified');