javascript - 面试题两则，求指教。。

问题描述

问 题

// ES5
var randy = new Person('Randy', 1995)
console.log(randy) // => {name: "Randy", birth: 1995}
randy.say('Hello') // => 'Randy: Hello'

// es6
var randy = new Person('Randy', 1995)

console.log(randy) // => {name: "Randy", birth: 1995}

randy.say('Hello') // => 'Randy: Hello'

console.log(randy.age) // => 22

randy.birth = 1998

console.log(randy.age) // => 19

分别用es5跟es6实现上面两个类

解决方案

// ES5
function Person(name,birth) {
    this.name = name;
    this.birth = birth;
}

Person.prototype.say = function (str) {
    console.log(this.name+':'+str);
}

var randy = new Person('Randy', 1995)
console.log(randy);
randy.say('Hello');



//ES6
class Person{
    constructor(name,birth,age){
        this.name = name;
        this.birth = birth;
    }
    get age(){
        return new Date().getFullYear() - Number(this.birth);
    }
    say(str){
        console.log(this.name+':'+str);
    }
}

var randy = new Person('Randy', 1995)
console.log(randy);
randy.say('Hello');
console.log(randy.age);
randy.birth = 1998;
console.log(randy.age);

推荐看看这个ES6 Class

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