功能代码集合

JS原型链

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function Person() {}
Person.prototype.name = "abc";
Person.prototype.sayName = function () {
  console.log(this.name);
};

let person = new Person();

person.__proto__ = Person.prototype;
String.__proto__ = Function.prototype;
String.constructor = Function;

JS继承

原型继承

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function Parent() {
  this.name = "Parent";
  this.sex = "male";
}

function Child() {
  this.name = "Child";
}

Child.prototype = new Parent();

构造函数继承

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function Parent(name) {
  this.name = name;
}

function Child() {
  Parent.call(this, "Child");
}

组合继承

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function Person(name) {
  this.name = name;
}

function Child(name) {
  Person.call(this, name);
}

Child.prototype = new Persion();
Child.prototype.constructor = Child;

new关键字

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function _new(constructor, ...arg) {
  let obj = {};
  obj.__proto__ = constructor.prototype;
  let res = constructor.apply(obj, arg);
  return Object.prototype.toString.call(res) === "[object Object]" ? res : obj;
}