原型链

用es5没有class，可以通过function构造函数去模拟class

function define(target, properties) {
    if (!Array.isArray(properties)) return;
    properties.forEach(property => {
        Object.defineProperty(target, property.key, {
            configurable: true,
            enumerable: false,
            value: property.value
        })
    });
}

function createClass(Constructor, protoProperties, staticProperties) {
    define(Constructor.prototype, protoProperties);
    define(Constructor, staticProperties);
}

const Animal = (function() {
    function Animal() {
        this.name = "老虎";
    }
    createClass(
        Animal, [{
            key: 'bark',
            value: () => {
                console.log('动物都会吃')
            }
        }], [{
            key: 'parent',
            value: 'Parent'
        }])

    return Animal;
})();

let animal = new Animal();
console.log(animal.name);
animal.bark();
console.log(Animal.parent);

继承

• Parent.call(this) 2.
• 原型重定向
• 静态重定向

function Tiger() {
    Animal.call(this);
}

function create(parentPrototype) {
    function Fn() {}
    Fn.prototype = parentPrototype;
    return new Fn();
}

Tiger.prototype = Object.create(Animal.prototype, { constructor: { value: Tiger } });

// Tiger.prototype = createPrototype(Animal.prototype);

let tiger = new Tiger();
console.log(tiger);
console.log(tiger.name);
console.log(Tiger.prototype.consstructor);
tiger.bark();

原型链

console.log(animal.__proto__ === Animal.prototype);
console.log(animal.__proto__.__proto__ === Object.prototype);
console.log(Object.prototype.__proto__);
console.log(Function.prototype.__proto__ === Object.prototype);
console.log(Function.__proto__ === Object.__proto__);
console.log(Animal.prototype.constructor === Animal);