Book Image

Mastering TypeScript - Fourth Edition

By : Nathan Rozentals
4.7 (3)
Book Image

Mastering TypeScript - Fourth Edition

4.7 (3)
By: Nathan Rozentals

Overview of this book

TypeScript is both a language and a set of tools to generate JavaScript, designed by Anders Hejlsberg at Microsoft to help developers write enterprise-scale JavaScript. Mastering Typescript is a golden standard for budding and experienced developers. With a structured approach that will get you up and running with Typescript quickly, this book will introduce core concepts, then build on them to help you understand (and apply) the more advanced language features. You’ll learn by doing while acquiring the best programming practices along the way. This fourth edition also covers a variety of modern JavaScript and TypeScript frameworks, comparing their strengths and weaknesses. You'll explore Angular, React, Vue, RxJs, Express, NodeJS, and others. You'll get up to speed with unit and integration testing, data transformation, serverless technologies, and asynchronous programming. Next, you’ll learn how to integrate with existing JavaScript libraries, control your compiler options, and use decorators and generics. By the end of the book, you will have built a comprehensive set of web applications, having integrated them into a single cohesive website using micro front-end techniques. This book is about learning the language, understanding when to apply its features, and selecting the framework that fits your real-world project perfectly.
Table of Contents (19 chapters)
17
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18
Index

Asynchronous Language Features

The JavaScript runtime, whether it is running in the browser, or whether it is running on a server through Node, is single threaded. This means that one, and only one, piece of code will be running at a particular time. This code runs in what is known as the main thread. JavaScript has also been built around an asynchronous approach, meaning that the main thread will not pause when requested to load a resource of some sort. It will, instead, place this request onto an internal queue, which will eventually be processed at a later point in time. While the single-threadedness of JavaScript may take a while to get your head around, it does take away the need for in-memory locking mechanisms, as are used in other languages to handle multiple threads of execution. This makes the JavaScript runtime a little easier to understand, and to work with.

The traditional JavaScript mechanism for dealing with asynchronous requests is through the callback mechanism...