SOURCE

Function.prototype.myapply =function(context){
    if(typeof this !== "function"){
        throw new Error("not a func");
    }
    context.fn = this;
    let res;
    if(arguments[1]){
        let args = Array.from(arguments).slice(1);
        res = context.fn(...args);
    }
    else{
        res = context.fn();
    }
    delete context.fn;
}
function me(){
    console.log(this,arguments);
}
let o1={a:1,name:'o1'};
let o2 = {a:2,name:'o2'};
me.myapply(o2,[1,2,3,4]);