Object.create

Object.create()方法创建一个新对象，使用现有的对象来提供新创建的对象的__proto__。

if (typeof Object.create !== "function") {
    Object.create = function (proto, propertiesObject) {
        if (typeof proto !== 'object' && typeof proto !== 'function') {
            throw new TypeError('Object prototype may only be an Object: ' + proto);
        } else if (proto === null) {
            throw new Error("This browser's implementation of Object.create is a shim and doesn't support 'null' as the first argument.");
        }

        if (typeof propertiesObject !== 'undefined') throw new Error("This browser's implementation of Object.create is a shim and doesn't support a second argument.");

        function F() {}
        F.prototype = proto;

        return new F();
    };
}

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由polyfill可以发现：

尽管Object.create支持第二个参数，但Object.create的polyfill不支持第二个参数
因为那些 ECMAScript5 以前版本限制，polyfill不支持第一个参数传入null

Reference: MDN - Object.create()open in new window

# Object.create

Object.create