You can configure your Gulp to allow Browsersync to help you develop. You can enable this in local.config.js, and filling in the url of your setup in usePackages.browsersync_localhost.

Above image is proudly copied from Smashing Magazine: 

Compony implements Browsersync in multiple ways:

It will update the CSS in the browser whenever you save a .scss file. and it will reload the page when:

  • You change a JavaScript or template file.
  • Gulp was triggered to rebuild Drupal's cache.

Hat tip: Browsersync will keep multiple browsers & devices in sync, so when you open the same url on a smartphone and a desktop, scrolling on the desktop will also scroll the mobile device. For this to work, you need to be connected to the same network.