有条件的事件发射器

我创建了一个事件发射器类。它工作正常。我来告诉你:

这是一节课:

class EventEmitter{

    constructor() {
        this.events = {};
    }

    on(eventName,callback) {
        if(this.events[eventName]) {
            this.events[eventName].push(callback);
        } else {
            this.events[eventName] = [callback]; 
        }
    }

    trigger(eventName, ...rest) {
        if(this.events[eventName]) {
            this.events[eventName].forEach(cb => {
                cb.apply(null,rest); 
            });
        }
    }
 }

有了这门课,我可以听一些事件。像这样:

 const ee = new EventEmitter();
 ee.on('change', (aa) => {
     console.log(aa);
 });

 ee.trigger('change','Argument');

现在我想听听有特定条件的事件。

例如:

 ee.on({'change': 'barack the boss'}, (aa) => {
     console.log(aa);
 });

以上代码位只应在触发器如下所示时执行:

 //wont run
 ee.trigger('change','barack is no boss');
//will run
 ee.trigger('change','barack the boss');

先谢谢你。

完整代码:

class EventEmitter{

    constructor() {
        this.events = {};
    }

    on(eventName,callback) {
        if(this.events[eventName]) {
            this.events[eventName].push(callback);
        } else {
            this.events[eventName] = [callback]; 
        }
    }

    trigger(eventName, ...rest) {
        if(this.events[eventName]) {
            this.events[eventName].forEach(cb => {
                cb.apply(null,rest); 
            });
        }
    }
 }

//events has been created and is currently an empty object
 const ee = new EventEmitter();

//even has been created, this event has a function which will be executed when event is triggered
 ee.on({'change': 'barack the boss'}, (aa) => {
     console.log(aa);
 });

 //wont run
 ee.trigger('change','barack is no boss');
//will run
 ee.trigger('change','barack the boss');