bound-prototype.js

class A {

    constructor(arg1, arg2, argn){
        console.log('A', typeof this.check)
        this.arg = arg1;
        this.bar = this.foo;
    }

    check(){
        console.log('this.foo',this.foo)
        console.log('this.args', this.arguments)
    }
}

// @see https://github.com/ProLoser/sinon/blob/3526a6b63986c50a34a8d160cd7b21e6de9129b1/lib/sinon/spy.js#L198
function callConstructorWithPresetThis (func, thisValue, args){
    // new a constructor `func` with `this` set to `thisValue` and args from `args
    // like new func.bind(thisValue, arg1, arg2, ...)
    // which is almost like `new func(arg1, arg2, ..)` - only with `thisValue` bound
    var ret = new (Function.prototype.bind.apply(func, [thisValue].concat(args)))
    return ret;
}

class B{}

var obj1 = Object.create(B.prototype);
var obj2 = Object.create(B.prototype);
obj1.foo = 'obj1';
obj2.foo = 'obj2';

var ret1 = callConstructorWithPresetThis(A, obj1, [1, 2])
console.log('ret', ret1);
console.log(ret1.arg)
console.log('thisValue', obj1);

var ret2 = callConstructorWithPresetThis(A, obj2, [10, 20, 30, 40])
console.log('ret', ret2);
console.log(ret2.arg)
console.log('thisValue', obj2);

console.log(
    'is of A', 
    obj1 instanceof A, 
    obj2 instanceof A, 
    ret1 instanceof A, 
    ret2 instanceof A, 
)

console.log(
    'is of B', 
    obj1 instanceof B, 
    obj2 instanceof B, 
    ret1 instanceof B, 
    ret2 instanceof B, 
)