SOURCE

function callback(payload) {
    console.log(`我收到事件了, 参数为 ${JSON.stringify(payload)}`);
}


class SubPub {
    subscribers = [];

    constructor() {

    }

    on(event, subscriber) {
        this.subscribers[event] = this.subscribers[event] || [];
        this.subscribers[event].push(subscriber);
    }

    off(event, subscriber) {
        if (this.subscribers[event]) {
            this.subscribers[event] = this.subscribers[event].filter(item => item !== subscriber);
        }
    }

    emit(event, payload) {
        if (this.subscribers[event]) {
            this.subscribers[event].forEach(item => {
                if (typeof item === "function") {
                    item(payload);
                }
            });
        }
    }
}


const pub = new SubPub();

pub.on('click', callback);
pub.on('click', callback);

pub.emit('click', { name: 'jack'} );

function test() {
    console.log('run test');
}

pub.on('move', test);

pub.emit('move');

pub.off('move', test);

pub.emit('move');

pub.emit('move');

pub.emit('click');