How to implement inheritance in javascript (code)

The content this article brings to you is about the implementation method (code) of JavaScript inheritance. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

There are many ways to implement inheritance in JS. The following are the more recommended methods. You can learn about other inheritance methods:

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

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

function People() {
    this.cls = 'people';
}

People.prototype.say = function(name) {
    name = name || this.cls;
    console.log('My class is '+ name);
}

function Student() {
    People.call(this);
    this.type = 'student';
}

inheritPrototype(Student, People);

Student.prototype.goToSchool = function() {
    console.log('I go to school every day.');
}

// 测试
var stu = new Student();

console.log('class: ' + stu.cls); // class: people
console.log('type: ' + stu.type); // type: student
stu.say(); // My class is people
stu.goToSchool (); // I go to school every day.

In fact, javascript has provided a simpler Implementation method, there is no need to reinvent the wheel here, and the method is not perfect, MDN example:

// Shape - 父类(superclass)
function Shape() {
  this.x = 0;
  this.y = 0;
}

// 父类的方法
Shape.prototype.move = function(x, y) {
  this.x += x;
  this.y += y;
  console.info('Shape moved.');
};

// Rectangle - 子类(subclass)
function Rectangle() {
  Shape.call(this); // call super constructor.
}

// 子类续承父类
Rectangle.prototype = Object.create(Shape.prototype);
Rectangle.prototype.constructor = Rectangle;

var rect = new Rectangle();

console.log('Is rect an instance of Rectangle?',
  rect instanceof Rectangle); // true
console.log('Is rect an instance of Shape?',
  rect instanceof Shape); // true
rect.move(1, 1); // Outputs, 'Shape moved.'

If you want to inherit multiple objects, you can use the mixing method:

function MyClass() {
     SuperClass.call(this);
     OtherSuperClass.call(this);
}

// 继承一个类
MyClass.prototype = Object.create(SuperClass.prototype);
// 混合其它
Object.assign(MyClass.prototype, OtherSuperClass.prototype);
// 重新指定constructor
MyClass.prototype.constructor = MyClass;

MyClass.prototype.myMethod = function() {
     // do a thing
};

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