Book Image

Learning TypeScript 2.x - Second Edition

By : Remo H. Jansen
Book Image

Learning TypeScript 2.x - Second Edition

By: Remo H. Jansen

Overview of this book

TypeScript is an open source and cross-platform statically typed superset of JavaScript that compiles to plain JavaScript and runs in any browser or host. This book is a step-by-step guide that will take you through the use and benefits of TypeScript with the help of practical examples. You will start off by understanding the basics as well as the new features of TypeScript 2.x. Then, you will learn how to work with functions and asynchronous programming APIs. You will continue by learning how to resolve runtime issues and how to implement TypeScript applications using the Object-oriented programming (OOP) and functional programming (FP) paradigms. Later, you will automate your development workflow with the help of tools such as Webpack. Towards the end of this book, you will delve into some real-world scenarios by implementing some full-stack TypeScript applications with Node.js, React and Angular as well as how to optimize and test them. Finally, you will be introduced to the internal APIs of the TypeScript compiler, and you will learn how to create custom code analysis tools.
Table of Contents (17 chapters)

Node.js development

In this section, we are going to look at a few small real-world examples of the usage of Node.js.

Working with the filesystem

We are going to implement a very small Node.js application. This application can be used as a search and replace tool. The result can be used as a command-line application and can be executed using the following command:

ts-node app.ts --files ./**/*.txt --find SOMETHING --replace SOMETHING_ELSE 

The application will replace one word for another in all the matching files. We are going to use the core filesystem API (fs) and two external npm modules:

  • glob is used to find files that match a given pattern
  • yargs is used to parse command-line arguments

We need to install both packages...