An example Shopify theme and corresponding workflow can be found here, created for PoptasticPop.com. Built on our proprietary Shopify Boilerplate theme (build on top of Dawn), this site uses the Shopify CLI and Webpack to develop Liquid, JSON, Sass, and JS code to a Shopify site. It uses TailwindCSS and AlpineJS to make a swell theme, the latest Sass and ES6 JS, and a Git action script to deploy to a parallel Git repo that can be easily connected to Shopify. Please look at the README on the Boilerplate for the latest workflow.
While this project did not require deployment to multiple domains, the Git action deploy system that it relies can easily be modified to deploy to multiple locations. For an example of this, please look at the deploy scripts used on the SmartSweets project. Each (see US and CA) is set to react to new tag-based releases on the Git branch and to deploy to corresponding parallel Git branches. We make use of an proprietary library to extend the Shopify CLI with .env variables and push and pull from both US and CA stores.
Before getting started on deployment, familiarize yourself with the README in the Shopify Boilerplate theme and install the following:
Node