Hello world with TypeScript

Now that you have all the tools at your disposal, let's write the ceremonial Hello World in TypeScript.

Creating the project

Open your favorite Terminal (again, we will assume Bash here). Create a new folder called hello-world:

$ mkdir hello-world

After the previous command, you can go into the newly created folder:

$ cd hello-world

Now open VS Code in the current folder using the code . command.

Hello (Type/Java)Script!

So, TypeScript is a superset of JavaScript, right? Let's see what that actually means by following these steps:

1. Create a new file called hello-world.ts:

The .ts file extension stands for TypeScript.

You can do it from within VS Code:

As you can see, VS Code directly recognizes TypeScript files:

2. Now add the following code to your newly created file:

var hello = "Hello world";

function say(something) {
 console.log(something);
}

say(hello);

Now let's do a silly thing: let's ask Node (our JavaScript interpreter) to execute our TypeScript code:

$ node hello-world.ts 

The output will be as follows:

That worked? Well, as you have probably guessed, this first example only contains JavaScript, which is why node doesn't have any issue.