Starting a TypeScript Project

In order to start a new TypeScript project, you'll probably want the typescript package installed. Run the below command to do so.

npm install -g typescript

\ Once that completes, you can verify the install was successful by running the command tsc --version. If everything went smoothly, you'll see something like the below, of course with whatever version you happened to install.

tsc --version
Version 3.8.3

Let's make some magic happen. Create a new file — app.ts — and add the following code in the file.

const accomplishment = () => {
  console.log(`You just made this program! High five!`);
}

accomplishment();

Great. We've got our TypeScript file, but it isn't something that Node can natively run. That's no problem though, we've got TypeScript installed to compile it to JavaScript — something Node does understand.

\ Run the below to compile app.ts.

tsc app.ts

\ You should see a new file — app.js — was created at that point — right next to your existing app.ts. You can now use node to natively run that with a simple...

node app.js

and you'll see the text "You just made this program! High five!" displayed in the terminal.

\ It's a small little program, literally just a few lines of code, but a program nonetheless — and a TypeScript one at that.

Navigate to the directory you want to create your new TypeScript project in and run the command

tsc --init

\ This will initialize that directory with a tsconfig.json file. That file tells the TypeScript compiler that this directory contains a TypeScript project, and that files within the directory can be compiled from TypeScript to JavaScript.