My preferred task runner these days when dealing with JavaScript projects is using npm scripts. However, getting them to run in parallel is a bit tricky since I tend to use both Linux and Windows.

With a package called npm-run-all, the setup is trivial:

{
  "scripts": {
    "watch": "npm-run-all -p watch:*",
    "watch:js": "...",
    "watch:css": "..."
  }
}

The above will run all of our watch tasks concurrently. If we need to run some tasks in sequence first, we can do this:

{
  "scripts": {
    "build": "npm-run-all build:clean -p build:js build:css",
    "build:clean": "...",
    "build:js": "...",
    "build:css": "..."
  }
}

The only downside seems to be that some programs may lose their colors if you don’t set it explicitly (with --colors, for example). I can’t say that I’m particularly bothered by that though.