npm watch can run background commands as though they were in the foreground

README.md

You can run this command with npm watch and it will run both the watchify command and the gulp watch command in two separate background processes but both process's output will still show up in the foreground. Since they're run through npm, you can hit ctrl+c to cancel the main process which in turn cancels the two background processes.

package.json

{
  "name": "...",
  "version": "...",
  "scripts": {
    "watch": "watchify -o app/bundle.js -v -d app/app.js & gulp watch",
  },
  ...
}