v0.14.3

Added

• Added an overlay that will display over the preview when we detect that
  service workers are not available. One reason this can happen is using
  Playground in Firefox private browsing mode, which does not support service
  workers (https://bugzilla.mozilla.org/show_bug.cgi?id=1320796).

• Added cursorPosition, cursorIndex, and tokenUnderCursor getters to
  <playground-code-editor>.

Changed

• Upgraded dependencies, including CodeMirror.

Fixed

• Fixed a bottleneck that prevented previews from loading until semantic
  TypeScript errors were computed. This should significantly improve the latency
  between updating a file and the new preview loading.

• Fixed bug where parent window history entries were added every time the
  preview reloaded.

• Improvements to service worker version updates:

  • The service worker will require less frequent updates going forward.
    Previously it needed updating for every playground-elements release. Now it
    only needs updating if the bytes of the service worker have changed between
    releases.

  • The default service worker scope has changed from
    <sandboxBaseUrl>/playground-project to
    <sandboxBaseUrl>/__playground_swfs_<serviceWorkerHash>. This should make service
    worker updates more reliable because old and new versions of service workers
    will no longer be in contention to control the same URLs.

  • Misc other small service worker robustness improvements, and additional
    logging to help debug future issues.