Node forman is abbreviated to nf.

yarn nf start

Setup and configuration

$ yarn install foreman

Put commands in your Procfile.

tsc: yarn tsc index.ts --watch --preserveWatchOutput
css: yarn sass --watch scss/index.scss:css/index.css
web: yarn node serve-static.js

Keys go to the output to differentiate logging from different processes.

5:29:51 PM tsc.1 |  $ /some/path/node_modules/.bin/tsc index.ts --watch --preserveWatchOutput
5:29:51 PM web.1 |  running a serve-static HTTP server on localhost:3000
5:29:52 PM tsc.1 |  5:29:52 PM - Starting compilation in watch mode...