DefinitelyTyped is a huge community project to type existing NPM packages and improve type re-use. Instead of having to write definitions yourself for the 1400 packages typed in DefinitelyTyped, you can just copy and paste them into your own project.
There's also a tool called TSD which allows you to install from DefinitelyTyped. Using tsd install node --save would install node/node.d.ts from DefinitelyTyped, and write the commit to a file called tsd.json.
Let's give it a go:
npm i -g tsd
tsd install node --save