The JavaScript language is changing, and among the changes are three new features which will revolutionize the way we write asynchronous code in JavaScript. The problem with the old callback-oriented asynchronous coding practice is the Callback Hell resulting from stacking callbacks within callbacks within callbacks. Between Promises, Generators and the proposed async/await feature, JavaScript programmers can largely free themselves from Callback Hell, and write clean asynchronous code that's easier to write, easier to understand, easier to maintain, and more robust.
That's a big promise - one that hinges on the fact that these three features:
- Flatten asynchronous code, eliminating the need for asynchronous callbacks contained within other asynchronous callbacks
- Automatically capturing and propagating thrown exceptions along the correct chain of execution
- Make asynchronous code look like synchronous code -- including asynchronous code in loop bodies
A new book - Asynchronous Node.js/JavaScript with ES-2015/2016 Promises, Generators and Async/Await - available through your available breed of Amazon-dot-com - focuses on how Promises, Generators and async/await functions can hugely improve our asynchronous JavaScript code.
The book has three major sections:
- Setting up required tools like Babel which handles transpiling advanced JavaScript so it can run on older JavaScript engines
- Implementation of several common code structures using different asynchronous JavaScript frameworks: the async library, Promises, Generators (with the co library), and async/await functions
- In-depth studies of using Generators with the co library in several useful/working programs
The table of contents is:
- Asynchronous flows in single-threaded JavaScript
- Asynchronous coding problems
- Brief overview of other ECMAScript-2015/2016 features
- Setting up Promises, Generators and more in Node.js and Browsers
- The async module and its many functions
- Promises as the basis of taming asynchronous JavaScript
- Generator functions
- Async/Await is the asynchronous programming feature we're all awaiting
- Asynchronous coding in the browser
- Synchronous execution of two AJAX calls
- In Depth: Asynchronous route handlers in Express
- In Depth: globfs makeover
- In Depth: Export a MySQL database query as CSV
- In Depth: Rendering Markdown to HTML through an EJS template
- In Depth: Converting code to the modern paradigm