一、prototype 是什么?
prototype
是每个函数(不包含箭头函数)都默认具备的属性,默认值为:指向函数自身的 constructor 对象。
1、查看 prototype
// 缺省值为:Rabbit.prototype = { constructor: Rabbit }function Rabbit() { }alert(Rabbit.prototype.constructor == Rabbit)// rabbit继承了constructorlet rabbit = new Rabbit();// 输入后果:truealert(rabbit.constructor == Rabbit);
2、谬误批改 prototype
对 prototype
不正确的批改,会导致 constructor
的扭转。
function Rabbit() { }// 1、谬误:这会笼罩整个 Rabbit.prototype,// Rabbit.prototype.constructor不能正确指向RabbitRabbit.prototype = { jumps: true};// 输入:falsealert(Rabbit.prototype.constructor === Rabbit);
3、正确批改 prototype
为了放弃constructor的正确性,不要笼罩prototype,而是用增加和删除操作
function Rabbit() { }// 1、正确:采纳增加操作// Rabbit.prototype.constructor==Rabbit没有被毁坏Rabbit.prototype.jumps = true// 输入:truealert(Rabbit.prototype.constructor === Rabbit);// 2、正确:采纳手动增加操作,等同于下面Rabbit.prototype = { jumps: true, constructor: Rabbit};alert(Rabbit.prototype.constructor === Rabbit);
4、用 constructor
创建对象
function Rabbit(name) { this.name = name; alert(name);}let rabbit = new Rabbit("White Rabbit");// constructor默认指向函数自身,下面和上面都是调用函数Rabbit创建对象let rabbit2 = new rabbit.constructor("Black Rabbit");
二、参考链接
- JavaScript的prototype是什么?