JavaScript Coding Standards

JSDoc

JSDoc is a markup language used to annotate JavaScript source code files. Using comments containing JSDoc, programmers can add documentation describing the application programming interface of the code they’re creating. https://jsdoc.app/index.html

Object

var foo;
let bar;
const FOO_BAR;

let obj = {};
var arr = [];

var VS let

console.log(foo); //undefined
var foo = 5;
console.log(foo); //5

console.log(bar); //error
let bar = 5;
console.log(bar); //5

Namespace

/** @namespace */
let webapp = {};

Class

/** @class */
webapp.Util = function () { 
	//property
	/** @type{Number} */
	foo: 0;
	
	//method
	/**
	 * @param {Number} e e.
	 * @returns {Number} e + 1.
	 */
	bar: function(e) {
		return e + 1;
	}
};

//Cara penggunaan
var obj = new webapp.Util();
var a = obj.foo; //0
/** @type{Number}*/
var b;

b = obj.bar(4); //5

Static Class

/** @class */
webapp.Util = function () { };

//property
/** @type{Number} */
webapp.Util.foo = 0;

//method
/**
 * @param {Number} e e.
 * @returns {Number} e + 1.
 */
webapp.Util.bar = function(e) {
	return e + 1;
};

//cara penggunaan
let a = webapp.Util.foo; //0
var b = webapp.Util.bar(5); //6

String

/** @type{String} */
var fooBar;
let foo = 'Foo';
let bar = 'Bar';

fooBar = foo + ' ' + bar; //Foo Bar
fooBar = `${foo} ${bar}`; //Foo Bar

Define Object

//gunakan [] untuk nullable
/**
 * @callback webapp.Util.FooBarCallback
 * @param {String} e e.
 * @returns {void}
 */
/**
* @typedef {Object} webapp.Util.FooBarParam
* @property {String} foo
* @property {String} bar
* @property {webapp.Util.FooBarCallback} [callback]
*/
/**
 * @param {String|webapp.Util.FooBarParam} args args.
 * @returns {String}
 */
webapp.Util.joinFooBar = function(args) {
	/** @type {String} */
	var fooBar;
	/** @type {webapp.Util.FooBarParam} */
	var param = {};
	
	switch (typeof args) {
        case 'string':
            param.foo = args;
            break;
        case 'object':
            param.foo = args.foo;
            param.bar = args.bar;
            param.callback = args.callback;
            break;
        default:
            console.error(`Unexpected type of argument! Expected String or Object, got ${typeof args}`);
            return;
    }
	
	if (typeof param.bar === 'string') {
		fooBar = `${param.foo} ${param.bar}`;
	} else {
		fooBar = param.foo;
	}
	
	if (typeof param.callback === 'function') {
		param.callback(fooBar);
	}
	
	return fooBar;
};