TypeScript Quick Start Guide

This article will show you how to quickly get up and running with TypeScript, and we will discuss the pros and cons of using TS. TypeScript is a superset of JavaScript and the TC39 standard. With TS, We are able to define both simple and complex static types for the variables in our code.

TypeScript is simply JavaScript with the optional addition of types for your variables. You can write in modern JavaScript syntax (ES2015+) when coding in TypeScript, and the compiler will convert the TypeScript (.ts) into JavaScript (.js) as well as offering the ability to transpile the JavaScript to previous versions such as ES5.

Note that if you are using module resolution such as require() or import/export for the browser, you will still need to use a bundler for the browser like Webpack, Rollup, or SystemJS.

Learn TypeScript - Best TypeScript Tutorials (2019) | gitconnected

Installing TypeScript

First install TypeScript using either npm:

npm install -g typescript

or yarn:

yarn global add typescript

Once installed globally, you will have the tsc command available in your terminal.

Compiling a .ts File

Using your terminal, create a new directory called ts-simple with the following command:

mkdir ts-simple

cd into this directory and create an index.ts file. Inside this file, we will create a function called sayHello with an argument name which is of type string.

Now use tsc to compile your index.ts:

tsc index.ts

This creates an index.js which has removed the typing from the sayHello function parameter as well as converted the file into ES5 code. The resulting JS file can be safely run on the browser or in Node. Your JavaScript file will look like…