I'm in the process of rewriting Tone.js in typescript. If you'd like to contribute to this effort, please check out this wiki article on getting started.

NPM:

npm install -D git://github.com/Tonejs/TypeScript.git

Yarn:

yarn add -D https://github.com/Tonejs/TypeScript.git

• Original definitions by Luke Phillips (thanks Luke!)
• Additinal help from @pmkary, @thSoft, @jasonfarrell (thanks all!)