Fahami mod N kemahiran js object inheritance_javascript

Artikel ini berkongsi N mod pewarisan objek js untuk rujukan anda.

1. Prototaip rantaian warisan

function Person(){};

Person.prototype = {
  constructor: Person,
  name: "Oliver"
};
    
function People(){};

People.prototype = new Person();
People.prototype.constructor = People;
People.prototype.sayName = function(){
  return this.name;
};

var ins = new People();

console.log(ins.sayName());

2. Meminjam pembina (objek palsu, warisan klasik)

1. Tiada parameter

function SuperType(){
  this.color = ["red","yellow","white"];
}
function SubType(){
  SuperType.call(this);
}

var instance1 = new SubType();
var instance2 = new SubType();

instance1.color.pop();
console.log(instance1.color); //["red", "yellow"]
console.log(instance2.color); //["red", "yellow", "white"]

2. Terdapat parameter

function SuperType(name){
  this.name = name;
  this.number = [21,32,14,1];
}
function SubType(name,age){
  SuperType.call(this,name);
  this.age = age;
}

var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);

instance2.number.pop();

console.log(instance1.name + instance1.age + instance1.number); //Oliver1821,32,14,1
console.log(instance2.name + instance2.age + instance2.number); //Troy2421,32,14

3. Warisan gabungan (warisan pseudo-klasik)

1. Tiada parameter

function SuperType(){
  this.color = ["red","yellow","white"];
}
SuperType.prototype.sayColor = function(){
  return this.color;
};

function SubType(){
  SuperType.call(this);
  this.number = 321;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayNumber = function(){
  return this.number;
};

var instance1 = new SubType();
var instance2 = new SubType();

instance2.color.pop();
console.log(instance1.color + instance1.number); //red,yellow,white321
console.log(instance2.color + instance2.number); //red,yellow321

2. Terdapat parameter

function SuperType(name){
  this.name = name;
  this.number = [32,1342,11,1];
}
SuperType.prototype.sayName = function(){
  return this.name;
};

function SubType(name,age){
  SuperType.call(this,name);
  this.age = age;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
SubType.prototype.sayAge = function(){
  return this.age;
};

var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);

instance2.number.pop();
console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver1832,1342,11,1
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy2432,1342,11

3. Warisan gabungan parasit (paradigma paling ideal untuk jenis rujukan)

function inheritPrototype(subType,superType){
  var prototype = Object(superType.prototype);
  prototype.constructor = subType;
  subType.prototype = prototype;
}

function SuperType(name){
  this.name = name;
  this.number = [321,321,43];
}
SuperType.prototype.sayName = function(){
  return this.name;
};

function SubType(name,age){
  SuperType.call(this,name);
  this.age = age;
}
inheritPrototype(SubType,SuperType);
SubType.prototype.sayAge = function(){
  return this.age;
};

var instance1 = new SubType("Oliver",18);
var instance2 = new SubType("Troy",24);
instance2.number.pop();

console.log(instance1.sayName() + instance1.sayAge() + instance1.number); //Oliver18321,321,43
console.log(instance2.sayName() + instance2.sayAge() + instance2.number); //Troy24321,321

Atau anda boleh menulis fungsi inheritPrototype seperti berikut:

function inheritPrototype(SubType,SuperType){
  SubType.prototype = new SuperType();
  SubType.prototype.constructor = SubType;
}

4. Warisan prototaip (digunakan untuk berkongsi nilai jenis rujukan, serupa dengan parasit)

1. Versi tradisional (takrifkan fungsi objek() dahulu, kemudian warisi)

function object(o){
  function F(){};
  F.prototype = o;
  return new F();
}

var SuperType = {
  name: "Oliver",
  number: [321,321,4532,1]
};

var SubType1 = object(SuperType);
var SubType2 = object(SuperType);

SubType1.name = "Troy";
SubType1.number.pop();

SubType2.name = "Alice";
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321321,321Oliver321,321

ECMAScript versi 5 (gunakan Object.create() terus dan kemudian warisi)

var SuperType = {
  name: "Oliver",
  number: [321,321,4532,1]
};

var SubType1 = Object.create(SuperType); //省略了定义object()函数
var SubType2 = Object.create(SuperType);

SubType1.name = "Troy";
SubType1.number.pop();

SubType2.name = "Alice";
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321321,321Oliver321,321

ECMAScript 5 versi singkatan (takrifkan parameter kedua Object.create() dan kemudian warisi)

var SuperType = {
  name: "Oliver",
  number: [321,321,4532,1]
};

var SubType1 = Object.create(SuperType,{
  name: {
    value : "Troy"
  }
});
var SubType2 = Object.create(SuperType,{
  name: {
    value : "Alice"
  }
});

SubType1.number.pop();
SubType2.number.pop();

console.log(SubType1.name + SubType2.name + SubType1.number + SubType2.number + SuperType.name + SuperType.number); //TroyAlice321,321321,321Oliver321,321

Warisan parasit (digunakan untuk berkongsi nilai jenis rujukan, serupa dengan prototaip)

function createAnother(original){
  var clone = Object(original);
  clone.sayHi = function(){
    return "Hi";
  };
  return clone;
}

var person = {
  name: "Oliver",
  number: [13,21,31,1]
};

var anotherPerson = createAnother(person);
anotherPerson.number.pop();

console.log(anotherPerson.sayHi() + anotherPerson.number); //Hi13,21,31
console.log(person.number); //13,21,31

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