Book Image

Javascript Unlocked

Book Image

Javascript Unlocked

Overview of this book

JavaScript stands bestride the world like a colossus. Having conquered web development, it now advances into new areas such as server scripting, desktop and mobile development, game scripting, and more. One of the most essential languages for any modern developer, the fully-engaged JavaScript programmer need to know the tricks, non-documented features, quirks, and best practices of this powerful, adaptive language. This all-practical guide is stuffed with code recipes and keys to help you unlock the full potential of JavaScript. Start by diving right into the core of JavaScript, with power user techniques for getting better maintainability and performance from the basic building blocks of your code. Get to grips with modular programming to bring real power to the browser, master client-side JavaScript scripting without jQuery or other frameworks, and discover the full potential of asynchronous coding. Do great things with HTML5 APIs, including building your first web component, tackle the essential requirements of writing large-scale applications, and optimize JavaScript’s performance behind the browser. Wrap up with in-depth advice and best practice for debugging and keeping your JavaScript maintainable for scaling, long-term projects. With every task demonstrated in both classic ES5 JavaScript and next generation ES6-7 versions of the language, Whether read cover-to-cover or dipped into for specific keys and recipes, JavaScript Unlocked is your essential guide for pushing JavaScript to its limits.
Table of Contents (15 chapters)
JavaScript Unlocked
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

JavaScript's built-in module system


Well, both AMD and CommonJS are community standards and not a part of the language specification. However, with EcmaScript 6th edition, JavaScript acquired its own module system. At the moment, no browser yet supports this feature, so we have to install the Babel.js transpiler to fiddle with the examples.

Since we already have Node.js that is distributed with NPM (the Node.js package manager), we now can run the following command:

npm install babel -g

Named exports

Now we can write a module as follows:

foo.es6

export let bar = "bar";
export let baz = "baz";

In ES6, we can export multiple elements. Any declaration prefixed with the keyword export becomes available for import:

main.es6

import { bar, baz } from "./foo";
console.log( bar ); // bar
console.log( baz ); // baz

Since we don't yet have any support for ES6 modules in the browser, we will transpile them into CommonJS or AMD. Here Babel.js helps us:

babel --modules common *.es6 --out-dir .

By this command...