JavaScript 实现简单的发布订阅模式

JS 实现简单的发布订阅模式

// 发布订阅模式
class EventEmitter {
  constructor() {
    this.listen = {};
  }

  on(name, callback) {
    this.listen[name]
      ? this.listen[name].push(callback)
      : (this.listen[name] = [callback]);
  }

  off(name, callback) {
    if (callback) {
      this.listen[name] = this.listen[name].filter(
        (params) => params != callback
      );
    } else {
      this.listen[name] = [];
    }
  }

  emit(name, params) {
    this.listen[name] && this.listen[name].map((callback) => callback(params));
  }
}

测试一下

let EventBus = new EventEmitter();
EventBus.on('message', (params) => {
  console.log(params);
});
EventBus.on('message', (params) => {
  console.log(params + 1);
});
EventBus.emit('message', 123);
EventBus.emit('message', 456);
EventBus.off('message');
EventBus.emit('message', 789);

输出