JavaScript中的proto、[[prototype]]和prototype | GCidea's blog

JerryXia 发表于 2018-02-12 20:42:42 , 阅读 (25)

__proto__与[[prototype]]相关介绍

　　待续。

一张图分析三者的关系

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.prototype === Foo.prototype);       //false

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.__proto__ === Foo.prototype);       //true

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.prototype);       //undefined

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.__proto__);       //object{}

function Foo(){
  console.log(1);
}
Foo.prototype = { };
var a = new Foo();
console.log(a.constructor === Foo);       //false

function Foo(){
  console.log(1);
}
Foo.prototype = { };
var a = new Foo();
console.log(a.constructor === Object);        //true

function Foo(){
  console.log(1);
}
Foo.prototype = { };
var a = new Foo();
console.log(a.constructor);

function Foo(){
  console.log(1);
}
Foo.prototype = { };
var a = new Foo();
console.log(a.__proto__);       //function Object() { [native code] }

function Foo(){
  console.log(1);
}
Foo.prototype = { };
var a = new Foo();
console.log(a.__proto__.__proto__ === Object.prototype);        //true

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.__proto__ === a.prototype);       //false

1 2	var a = new Function(); console.log(a.__proto__ === Function.prototype); //true

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.constructor.prototype === a.__proto__);        //true

function Foo(){
  console.log(1);
}
var a = new Foo();
console.log(a.constructor.prototype === Foo.prototype);        //true

[ 技术文章推荐 ]