This is how javascripts `new` operator works

New.js

function New(constructor) {
	if (typeof constructor !== 'function') {
		throw new TypeError("'"+ constructor +"' is not a constructor")
	}
	var obj = {}
	obj.__proto__ = constructor.prototype
	var res = constructor.apply(obj, [].slice.call(arguments, 1))
	if (typeof res === "object") {
		return res
	}
	return obj
}