The initial instructions says to use browserify. I may have things installed incorrectly but I could never get it to work: C:\Users\xxx\node\node_modules\prosemirror>browserify --outfile …/…/public/demo-built.js demo/demo.js
C:\Users\xxx\node\node_modules\prosemirror\demo\demo.js:1 import {ProseMirror} from “…/src/edit/main” ^ ParseError: ‘import’ and ‘export’ may appear only with ‘sourceType: module’
However ‘npm run demo’ works and is better for development because of watchify.