prototype与__proto__区别详细介绍-创新互联

prototype与__proto__区别

Each constructor is a function that has a property named “prototype” that is used to implement prototype-based inheritance and shared properties. Every object created by a constructor has an implicit reference (called the object's prototype) to the value of its constructor's “prototype” property.
When a constructor creates an object, that object implicitly references the constructor's prototype property for the purpose of resolving property references. The constructor's prototype property can be referenced by the program expression constructor.prototype, and properties added to an object's prototype are shared, through inheritance, by all objects sharing the prototype. Alternatively, a new object may be created with an explicitly specified prototype by using the Object.create built-in function. –ECMAScript® 2015 Language Specification

__proto__是每个对象都有的一个属性，而prototype是函数才会有的属性!!!

使用Object.getPrototypeOf()代替__proto__!!!

一、prototype

几乎所有的函数（除了一些内建函数）都有一个名为prototype（原型）的属性，这个属性是一个指针，指向一个对象，而这个对象的用途是包含可以有特定类型的所有实例共享的属性和方法。prototype是通过调用构造函数而创建的那个对象实例的原型对象。hasOwnProperty()判断指定属性是否为自有属性；in操作符对原型属性和自有属性都返回true。

示例：自有属性&原型属性

var obj = {a: 1};
obj.hasOwnProperty("a"); // true
obj.hasOwnProperty("toString"); // false
"a" in obj; // true
"toString" in obj; // true

另外有需要云服务器可以了解下创新互联建站www.cdcxhl.com，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。