minte9
LearnRemember



Constructor

Classes are a more advance object construct (unlike new function()). 
 
/**
 * Classes
 * 
 * In JavaScript, a class is a special kind of function
 * The constructor() method is called automatically by new
 * No comma required between class methods
 * Classe always use strict
 */

class User 
{
    constructor (name) {
        this.name = name;
    }

    hello() {
        console.log("Hi, this is " + this.name);
    }
}
 
let a = new User("Mihai");
let b = new User("John");

a.hello(); // Hi, this is Mihai
b.hello(); // Hi, this is John

Getter

Just like literal objects, classes may include getters and setters. 
 
/**
 * Get/Set
 * 
 * Technically, such class declaration works by creating 
 * getters and setters in MyClass.prototype
 */

class MyClass
{
    constructor (msg) {
        this.msg = msg; // invokes the setter
    }

    set msg(str) {
        str = str.toUpperCase();
        this._msg = str; // Look Here
    }

    get msg() {
        return this._msg;
    }
}
 
let obj = new MyClass("hello world");

try {
    console.log(obj.msg + "!"); // HELLO WORLD!
    console.log(obj.msg());
} catch (err) {
    console.log(err.message); // obj.msg is not a function
}



  Last update: 297 days ago