SOURCE

Function.prototype.myBind= function(obj,...args){
      let self = this
        let fn=() =>{
            self.call(obj,...args)
        }
        fn.prototype={...self.prototype}
        return fn
    }
function foo(c){
    console.log(this.a,c)
    return c
}

let a = {
    a:1,
    b:2
}

console.log(foo.myBind(a,3))