原型链继承
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());
借用构造函数(伪造对象,经典继承)
无参数
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"]
有参数
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
组合继承(伪经典继承)
无参数
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
有参数
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
寄生组合式继承(引用类型最理想的范式)
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
或者可以把inheritPrototype 函数写成下面这样:
function inheritPrototype(SubType,SuperType){
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;
}
原型式继承(用于共享引用类型的值,与寄生式类似)
传统版(先定义object()
函数,再继承)
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 5 版(直接用Object.create()
,再继承)
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 简写版(定义Object.create()的第二个参数,再继承)
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
寄生式继承(用于共享引用类型的值,与原型式类似)
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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