Book Image

Learn TypeScript 3 by Building Web Applications

By : Sebastien Dubois, Alexis Georges
Book Image

Learn TypeScript 3 by Building Web Applications

By: Sebastien Dubois, Alexis Georges

Overview of this book

TypeScript is a superset of the JavaScript programming language, giving developers a tool to help them write faster, cleaner JavaScript. With the help of its powerful static type system and other powerful tools and techniques it allows developers to write modern JavaScript applications. This book is a practical guide to learn the TypeScript programming language. It covers from the very basics to the more advanced concepts, while explaining many design patterns, techniques, frameworks, libraries and tools along the way. You will also learn a ton about modern web frameworks like Angular, Vue.js and React, and you will build cool web applications using those. This book also covers modern front-end development tooling such as Node.js, npm, yarn, Webpack, Parcel, Jest, and many others. Throughout the book, you will also discover and make use of the most recent additions of the language introduced by TypeScript 3 such as new types enforcing explicit checks, flexible and scalable ways of project structuring, and many more breaking changes. By the end of this book, you will be ready to use TypeScript in your own projects and will also have a concrete view of the current frontend software development landscape.
Table of Contents (15 chapters)

Leveraging TypeScript path mappings

Our imports already look much better because we have created barrels, which remove the need for knowing the exact filenames. However, our imports still need to indicate the relative paths to the packages that we want to import symbols from.

This is far from ideal because as your applications grow in complexity, your paths will be longer and longer and you might end up with imports like this: import { foo } from '../../../../../services';.

A good IDE will go a long way to diminish the annoyance, but it will still have an impact on readability and refactoring. Fortunately, we can improve the situation by adapting the compiler's configuration.

In tsconfig.json, we can configure the paths option in order to define mappings. Those mappings will let us use non-relative imports (for example, services).

The paths mapping values are relative...