The library perspectives-serviceworker enables pages in a webbrowser that does not support SharedWorkers (viz Safari) to communicate with another.
Furthermore, the library perspectives-serviceWorker is used to make InPlace into a Progressive Web App (it caches files).
Install with npm:
$ npm install perspectives-workers
Each InPlace page registers the serviceworker.
Create dist/perspectives-sharedworker.js by evaluating on the command line:
$ npm run build
This is equivalent to:
$ npx webpack
Have Webpack watch the sources and update dist/perspectives-sharedworker.js by evaluating on the command line:
$ npm run watch
This is equivalent to:
$ npx webpack --watch