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

Integration compiler options

There are a few compiler options that we can configure in order to help with the integration of JavaScript and TypeScript. These options will allow us to include JavaScript files within the same project as TypeScript files, as well as allowing us to do some type checking on JavaScript files. We are also able to generate declaration files from our TypeScript code, if we are building libraries for general consumption. In this section of the chapter, we will explore these compiler options.

The allowJs and outDir options

The default TypeScript compilation configuration, as seen in the tsconfig.json file, will generate JavaScript files in the same directory as the source TypeScript files. The outDir compilation option is used to specify a different output directory for the generated JavaScript, as follows:

{
    "compilerOptions": {
        "target": "es5", 
        "module": "commonjs", 
      ...