Mario Martinez ilmoralito

The Revealing Module Pattern in Javascript

Zach Caceres

Javascript does not have the typical 'private' and 'public' specifiers of more traditional object oriented languages like C# or Java. However, you can achieve the same effect through the clever application of Javascript's function-level scoping. The Revealing Module pattern is a design pattern for Javascript applications that elegantly solves this problem.

The central principle of the Revealing Module pattern is that all functionality and variables should be hidden unless deliberately exposed.

Let's imagine we have a music application where a musicPlayer.js file handles much of our user's experience. We need to access some methods, but shouldn't be able to mess with other methods or variables.

Using Function Scope to Create Public and Private Methods

Basic CRUD operations with PDO

CRUD = Create, Read, Update, Delete

Open a database connection

$host = '127.0.0.1';
$dbname = 'test';
$username = 'root';

	{
	"keys": ["ctrl+alt+l"],
	"command": "toggle_setting",
	"args": {
	"setting": "line_numbers"
	}

	#
	# If all files excluded and you will include only specific sub-directories
	# the parent path must matched before.
	#

	/**
	!/.gitignore

	###############################
	# Un-ignore the affected subdirectory

	def (a,b,rest) = [0, 1, 2..-1].collect { [1,2,3,4][it] }

	assert a == 1
	assert b == 2
	assert rest == [3,4]

	@Grab(group='com.github.groovy-wslite', module='groovy-wslite', version='1.1.0')
	@Grab(group='joda-time', module='joda-time', version='2.7')
	import wslite.rest.*
	import org.joda.time.*
	import org.joda.time.format.*
	import groovy.xml.*
	import groovy.json.*
	import static java.lang.System.*
	import groovy.transform.*

	<?php

	if (!function_exists('array_group_by')) {
	/**
	* Groups an array by a given key.
	*
	* Groups an array into arrays by a given key, or set of keys, shared between all array members.
	*
	* Based on {@author Jake Zatecky}'s {@link https://github.com/jakezatecky/array_group_by array_group_by()} function.
	* This variant allows $key to be closures.

	# Backup
	docker exec CONTAINER /usr/bin/mysqldump -u root --password=root DATABASE > backup.sql

	# Restore
	cat backup.sql \| docker exec -i CONTAINER /usr/bin/mysql -u root --password=root DATABASE

	/*
	Template literals if-statement example
	Using a single-line conditional, we can create an if-statements within template literals.
	*/

	function makeHTML(title) {
	return `
	${title ? `
	This element has a title, and it is "${title}"
	` : `

	// 🔥 Node 7.6 has async/await! Here is a quick run down on how async/await works

	const axios = require('axios'); // promised based requests - like fetch()

	function getCoffee() {
	return new Promise(resolve => {
	setTimeout(() => resolve('☕'), 2000); // it takes 2 seconds to make coffee
	});
	}