Object & prototype & __proto__ All In One

Object & prototype & proto All In One

js 原型，原型链，原型对象

const obj ={};
// {}

const obj = new Object();
// {}
obj.prototype;
// undefined

obj.__proto__;
/*
{constructor: ƒ, __defineGetter__: ƒ, __defineSetter__: ƒ, hasOwnProperty: ƒ, __lookupGetter__: ƒ, …}
constructor: ƒ Object()
hasOwnProperty: ƒ hasOwnProperty()
isPrototypeOf: ƒ isPrototypeOf()
propertyIsEnumerable: ƒ propertyIsEnumerable()
toLocaleString: ƒ toLocaleString()
toString: ƒ toString()
valueOf: ƒ valueOf()
__defineGetter__: ƒ __defineGetter__()
__defineSetter__: ƒ __defineSetter__()
__lookupGetter__: ƒ __lookupGetter__()
__lookupSetter__: ƒ __lookupSetter__()
get __proto__: ƒ __proto__()
set __proto__: ƒ __proto__()
*/

Object.prototype;
/*
{constructor: ƒ, __defineGetter__: ƒ, __defineSetter__: ƒ, hasOwnProperty: ƒ, __lookupGetter__: ƒ, …}
constructor: ƒ Object()
hasOwnProperty: ƒ hasOwnProperty()
isPrototypeOf: ƒ isPrototypeOf()
propertyIsEnumerable: ƒ propertyIsEnumerable()
toLocaleString: ƒ toLocaleString()
toString: ƒ toString()
valueOf: ƒ valueOf()
__defineGetter__: ƒ __defineGetter__()
__defineSetter__: ƒ __defineSetter__()
__lookupGetter__: ƒ __lookupGetter__()
__lookupSetter__: ƒ __lookupSetter__()
get __proto__: ƒ __proto__()
set __proto__: ƒ __proto__()

*/

obj[`Prototype`];
// undefined
obj[[`Prototype`]];
// undefined


obj.__proto__ === Object.prototype;
// true

obj.__proto__.prototype === Object.prototype;
// false

obj.__proto__.prototype == Object.prototype;
// false

Object.prototype.__proto__;
// null
obj.__proto__.__proto__;
// null

Object.prototype.prototype;
// undefined
obj.__proto__.prototype;
// undefined

Function

constructor

obj.prototype;
// undefined

Object.__proto__;
// ƒ () { [native code] }

Object.__proto__;
// ƒ () { [native code] }


function func() {}

func;
// ƒ func() {}

func.__proto__;
// ƒ () { [native code] }

func.prototype;
// {constructor: ƒ}

Object.__proto__ === func.__proto__;
// true

Object.__proto__ === Function.prototype;
// true

Function.__proto__;
// ƒ () { [native code] }

Function.prototype;
// ƒ () { [native code] }


func.__proto__ === Function.__proto__;
// true
func.__proto__ === Function.prototype;
// true

Object multi inherit

Array is Object child

const arr = [];
// []

arr.__proto__;
// [constructor: ƒ, concat: ƒ, copyWithin: ƒ, fill: ƒ, find: ƒ, …]

arr.__proto__.__proto__;
// {constructor: ƒ, __defineGetter__: ƒ, __defineSetter__: ƒ, hasOwnProperty: ƒ, __lookupGetter__: ƒ, …}

arr.__proto__.__proto__.__proto__;
// null

prototype & proto & constructor All In One

refs

1. Object & prototype & proto

2. Function & prototype & Object

https://zh.javascript.info/native-prototypes

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