ES 6人学習整理(八)——Class

構文

基本構文の例

// Person.js
export default class {
    constructor(name, age) {
        this.name = name;
        this.age = age;
    }
    getName() {
        return this.name;
    }
    setName(name) {
        this.name = name;
    }
    getAge() {
        return this.age;
    }
    setAge(age) {
        this.age = age;
    }
    say() {
        return `My name is ${this.name}, I'm ${this.age} years old!`;
    }
}

// test.js
import Person from './Person';
let person = new Person('Zhang San', 18);
person.getName();   // Zhang San
person.getAge();    // 18
person.setName('Li Si');
person.getName();   // Li Si
person.setAge(19);  // 19
person.say();       // My name is Li Si, I'm 19 years old!
// js Java 

継承

// Student.js
import Person from './Person';
export default class extends Person {
    constructor(name, age, teacher) {
        super(name, age);
        this.teacher = teacher;
    }
    getTeacher() {
        return this.teacher;
    }
    setTeacher(teacher) {
        this.teacher = teacher;
    }
    say() {
        return `My name is ${this.name}, I'm ${this.age} years old, and my teacher is ${this.teacher}!`;
    }
}

// test.js
import Student from './Student';
let student = new Student('Zhang San', 19, 'Mr Tian');
student.say();  // My name is Zhang San, I'm 19 years old, and my teacher is Mr Tian!
//  java， ， 
//  ， ， ~~

スタティツクメソッド

クラス内のメソッドの前にstaticキーワードを追加します.このメソッドはインスタンスに継承されず、クラスのみで呼び出されます(サブクラスで直接クラス名でアクセスできます).静的メソッドと呼ばれます.

// Person.js
export default class {
    static test() {
        return 'Test static method';
    }
}

// Student.js
import Person from './Person';
Person.test();
export default class extends Person {
    say() {
        Person.test();
    }
}