发布订阅者模式 -- 简单的PubSub

/**
 * 发布订阅者模式
 *
 **/
interface handle {
    [propName: string]: Function[]
}
class PubSub {
    private handles: handle = {};

    // Subscribe to events
    subscribe(eventName: string, handle: Function) {
        if (!this.handles.hasOwnProperty(eventName)) {
            this.handles[eventName] = []
        }
        if (typeof handle === 'function') {
            this.handles[eventName].push(handle)
        }
        else {
            throw new Error('missing callback')
        }
        return this
    }

    // Publish event
    publish(eventName: string, ...rest: any[]) {
        if (this.handles.hasOwnProperty(eventName)) {
            this.handles[eventName].forEach( (item) => {
                item.apply(null, rest);
            })
        }
        else {
            throw new Error(eventName.concat(' event not registered'))
        }
        return this
    }

    // Remove event
    remove(eventName: string, handle: Function) {
        if (!this.handles.hasOwnProperty(eventName)) {
            throw new Error(eventName.concat(' event not registered'))
        }
        else if (typeof handle !== 'function'){
            throw new Error('miss callback')
        }
        else {
            this.handles[eventName].forEach((item, index, arr) => {
                if (item === handle) {
                    arr.splice(index, 1)
                }
            })
        }
        return this
    }
}

let pubSub = new PubSub()

pubSub.subscribe('change', function (val) {
    console.log(`你订阅的值是：${ val }`)
})
pubSub.publish('change', 'lihua')