SOURCE

Function.prototype.call = function() {
    var ctx = arguments[0] || window
    var args = []
    for(var i = 1; i < arguments.length; i++){
        args.push('arguments[' + i +']')
    }
    ctx.fn = this
    var result = eval('ctx.fn(' + args +')')
    delete ctx.fn
    return result
}

Function.prototype.apply = function(ctx, arr) {
    var ctx = ctx || window
    var args = []
    for(var i = 0; i < arr.length; i++){
        args.push('arr[' + i +']')
    }
    ctx.fn = this
    var result = eval('ctx.fn(' + args +')')
    delete ctx.fn
    return result
}

function foo () {
    console.log('this.name:', this.name)
    console.log('arguments:', [...arguments])
    return 'I am back.'
}

const obj = {
    name: 'obj name'
}

const result = foo.apply(obj, [1, 2, 'c'])
console.log(result)