feat(v2): Plugin for Offline/PWA support (#2205)

* implement PWA plugin

* added pwa support for docusaurus website

* moved sw registration to client module

* moved compile function to webpack util

* build sw using webpack and render pwa popup

* implement @theme/PwaReloadPopup

* update website sw to use modules

* updated pwa readme

* fix header lint errors

* apply code formatting

* cache files only for mobile, saveData, or installed pwa

* added comments about clearing registrations

* fixed prettier error

* updated pwa README

* fix README JS

* move /blog => /blog/index.html logic to else branch

* add `alwaysPrecache` option

* updated docusaurus-plugin-pwa version

* added pwa to using-plugins.md

* review fixes

* re-disable restricted-globals to use self in service worker

* useless doc

* Update packages/docusaurus-plugin-pwa/README.md

Co-authored-by: Reece Dunham <me@rdil.rocks>

* Update packages/docusaurus-plugin-pwa/README.md

* update a bit pwa doc + minor refactors

* minor refactors + add workbox debug mode

* env PWA_ prefix

* typo

* minor refactor

* fix file output

* add serve:v2:ssl yarn command

* minor pwa fixes

* typo

* add dynamic import comment in SW

* comment

* let the PWA plugin implement its reload popup on his own

* pwa: add Joi options validation

* pwa plugin should have its own webpack/babel custom setup

* PWA:
- debug logs
- better SW params system
- offline mode activation strategies
- docs

* add pwa install gif

* pwa: popup -> reloadPopup + minor refactors

* fix process.env reading + better debug log

* minor fixes

* minor changes

* minor changes

Co-authored-by: slorber <lorber.sebastien@gmail.com>
Co-authored-by: Sébastien Lorber <slorber@users.noreply.github.com>
Co-authored-by: Reece Dunham <me@rdil.rocks>

website/src/sw.js

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {registerRoute} from 'workbox-routing';
+import {StaleWhileRevalidate} from 'workbox-strategies';
+
+export default function swCustom(params) {
+  if (params.debug) {
+    console.log('[Docusaurus-PWA][SW]: running swCustom code', params);
+  }
+
+  // Cache responses from external resources
+  registerRoute((context) => {
+    return [
+      /graph\.facebook\.com\/.*\/picture/,
+      /netlify\.com\/img/,
+      /avatars1\.githubusercontent/,
+    ].some((regex) => context.url.href.match(regex));
+  }, new StaleWhileRevalidate());
+}