[[Construct]]

ctor.js

// 注意: アロー関数を排除できない
function ctor (Ctor) {
	return function () {
		if(typeof Ctor !== "function") {
			throw new TypeError(typeof Ctor + " is not a function");
		}
		var proto = Ctor.prototype;
		if (proto === null || typeof proto !== "object") {
			proto = Object.prototype;
		}
		var obj = Object.create(proto);
		var result = Ctor.apply(obj, arguments);
		if (result === null || typeof result !== "object") {
			return obj;
		}
		else {
			return result;
		}
	};
}