Book Image

The TypeScript Workshop

By : Ben Grynhaus, Jordan Hudgens, Rayon Hunte, Matt Morgan, Vekoslav Stefanovski
5 (1)
Book Image

The TypeScript Workshop

5 (1)
By: Ben Grynhaus, Jordan Hudgens, Rayon Hunte, Matt Morgan, Vekoslav Stefanovski

Overview of this book

By learning TypeScript, you can start writing cleaner, more readable code that’s easier to understand and less likely to contain bugs. What’s not to like? It’s certainly an appealing prospect, but learning a new language can be challenging, and it’s not always easy to know where to begin. This book is the perfect place to start. It provides the ideal platform for JavaScript programmers to practice writing eloquent, productive TypeScript code. Unlike many theory-heavy books, The TypeScript Workshop balances clear explanations with opportunities for hands-on practice. You’ll quickly be up and running building functional websites, without having to wade through pages and pages of history and dull, dry fluff. Guided exercises clearly demonstrate how key concepts are used in the real world, and each chapter is rounded off with an activity that challenges you to apply your new knowledge in the context of a realistic scenario. Whether you’re a hobbyist eager to get cracking on your next project, or a professional developer looking to unlock your next promotion, pick up a copy and make a start! Whatever your motivation, by the end of this book, you’ll have the confidence and understanding to make it happen with TypeScript.
Table of Contents (16 chapters)
Preface

Promisify

Promisification is the practice of taking an asynchronous function that expects a callback and turning it into a promise. This is essentially a convenience utility that allows you to always write in promises instead of having to use the callbacks of a legacy API. It can be really helpful to promisify legacy APIs so that all our code can use promises uniformly and be easy to read. But it's more than just a convenience to convert callbacks into promises. Some modern APIs will only accept promises as parameters. If we could only work on some code with callbacks, we would have to wrap the callback asynchronous code with promises manually. Promisification saves us the trouble and potentially many lines of code.

Let's work through an example of promisifying a function that expects a callback. We have a few options to choose from. Bluebird again provides this functionality with Promise.promisify. This time, we'll try a polyfill, es6-promisify. Let's start...