Start by intsalling typescript
$ npm install -g typescript
make a typescript file, e.g. filename.ts
let num: number = 4;
$ tsc filename.ts
and you’ll get a new file filename.js
var number = 4;
and that’s it!
What’s great about typescript is it gives you the errors on transpile.
Try this in your file,
without defining blah so that you get an error.
Note that the file will still run despite error showing.