N.B. This is not a polyfill. This transform aims to provide a future-proof way of using a limited subset of the features provided by native CSS variables.
npm install sheetify-variables
As a sheetify transform:
var variables = ;var sheetify = ;;
var myVars ='app-bg-color': 'white';;
Setting preserve to true will preserve the variable definitions and references in the output, so that they can be used by supporting browsers.