TypeError: this.$input.data(...).map is not a function
and after that, a warning:
Source map error: request failed with status 404
Resource URL: http://localhost/wp/wp-content/plugins/real-media-library/public/lib/es7-shim/dist/es7-shim.min.js
Source Map URL: dist/es7-shim.map
When I disable WP Real Media Library, everything works as expected.
Thanks, I just noticed that I had an older version (4.0.5) of WP Media Library installed. Easy to miss, since it's a premium plugin without auto-update. Updating to the latest version fixed the issue (it now works both with and without your fix).