export const PubSub = {
    id:1,
    callbacks:{
        // pay:{
        //     token_1:fn,
        //     token_2:fn2
        // }
    }
}
//订阅
PubSub.subscribe = function(channel,callback){
    let token = "token_" + this.id++
    if(this.callbacks[channel]){
        this.callbacks[channel][token] = callback
    }else{
        this.callbacks[channel] = {
            [token]:callback
        }
    }
    return token
}
//发布
PubSub.publish = function(channel,data){
    if(this.callbacks[channel]){
        Object.values(this.callbacks[channel]).forEach(callback=>{
            callback(data)
        })
    }
}
/**
 * 取消订阅
 * @param {*} flag 
 */
PubSub.unsubscribe = function(flag){
    if(flag === undefined){
        this.callbacks = {}
    }else if(typeof flag === 'string'){
        if(flag.indexOf('token_') === 0){
            let callbackObj = Object.values(this.callbacks).find(obj=>obj.hasOwnProperty(flag))
            if(callbackObj){
                delete callbackObj[flag]
            }
        }else{
            delete this.callbacks[flag]   
        }
    }
}