SOURCE

class  subscripe {
    constructor (){
        this.pood = []
    }
    add(fn){
        let index = this.pood.indexOf(fn);
        index>0 ?null : this.pood.push(fn);
    }
    remove(fn){
        let index = this.pood.indexOf(fn);
        index>0 ? this.pood.splice(index,1) : null;
    }
    fire(...arg){
        this.pood.forEach(item=>{
              item(...arg);
        }
    )    
    }
}
let sub = new subscripe();
let fn1 =(...arg)=>{
    console.log(1,arg) 
}
let fn2 =(...arg)=>{
    console.log(2,arg)
}
let fn3 =(...arg)=>{
    console.log(3,arg)
}
sub.add(fn1)
sub.add(fn2)
sub.add(fn3)
sub.fire(10,20)
sub.remove(fn2)
sub.fire(10,20)