SOURCE

Function.prototype.call2 = function (context) {
    context = context || window;
    context.fn = this;
    let args = Array.prototype.slice.call(arguments, 1);
    context.fn(...args);
    delete context.fn;
}
Function.prototype.bind2 = function (context) {
    self = this;
    let args = Array.prototype.slice.call(arguments, 1);
    let NullFn = function () {}
    let Fb = function () {
        let bindArgs = Array.prototype.slice.call(arguments);
        return self.apply(this instanceof Fb ? this : context, args.concat(bindArgs));
    };
    NullFn.prototype = self.prototype;
    Fb.prototype = new NullFn();
    return Fb;
}
var obj = {
    name: 'DreamFox',
    age: 28
};
function sayA(name) {
    console.log("I'm %s, %d years old", name, this.age);
}
sayA();
sayA.call2(obj, 'wangxin');

var value = 2;

var foo = {
    value: 1
};

function bar(name, age) {
    this.habit = 'shopping';
    console.log(this.value);
    console.log(name);
    console.log(age);
}

bar.prototype.friend = 'kevin';

var bindFoo = bar.bind2(foo, 'daisy');

var obj = new bindFoo('18');