Create an object in the form of a constructor
Disadvantages: adding attributes is too cumbersome
var obj = new Object();
obj.name = "libai";
obj.age = 12;
// 添加属性繁琐 -> 字面量形式
var obj1 = {
name: "libai",
age: 12
}
var obj2 = {
name: "libai",
age: 12
}
Two function construction (factory mode)
Disadvantages: unable to distinguish the same attribute name of different functions
function createCat(name, age){
return {
name,
age
}
}
var cat1 = createCat("Tom", 12);
var cat2 = createCat("Jack", 16);
function createDog(name, age){
return {
name,
age
}
}
var dog1 = createDog("金毛", 6);
var dog2 = createDog("黑毛", 6);
Three constructor mode
Disadvantages: unable to provide shared attributes and methods for the instance, wasting memory
function Cat(name, age){
this.name = name;
this.age = age;
this.hobby = ["eat fish", "eat mouse"];
this.skill = function (){
console.log("爬树");
}
}
var cat3 = new Cat("蓝", 12);
var cat4 = new Cat("红", 6);
function Dog(name, age){
this.name = name;
this.age = age;
}
var dog3 = new Dog("流浪", 12);
console.log(cat3, dog3);
console.log(cat3.hobby === cat4.hobby); // false
console.log(cat3.skill === cat4.skill); // false
Four constructor + prototype
Advantages: The constructor adds private properties to the instance, and the prototype provides common properties
function Person(name, age){
this.name = name;
this.age = age;
this.hobby = [];
}
Person.prototype.skill = ["eat", "sleep"];
Person.prototype.run = function (){
console.log("run");
}
var zs = new Person("张三", 12);
var lb = new Person("李白", 16);
console.log("zs.hobby === lb.hobby", zs.hobby === lb.hobby); // false
console.log("zs.skill === lb.skill", zs.skill === lb.skill); // true
console.log("zs.run === lb.run", zs.run === lb.run); // true
lb.hobby.push("drink");
console.log(zs.hobby);