Ready for a demo! Has an in-context sidebar.

Uses webpack 5 module federation to dynamically load code based on a JS file URL.

package.json

@@ -62,7 +62,7 @@
     "truncate-html": "1.0.3"
   },
   "devDependencies": {
-    "@edx/frontend-build": "5.5.5",
+    "@edx/frontend-build": "git+https://github.com/edx/frontend-build.git#alpha",
     "@testing-library/dom": "7.16.3",
     "@testing-library/jest-dom": "5.10.1",
     "@testing-library/react": "10.3.0",

src/courseware/course/Course.jsx

@@ -105,6 +105,7 @@ function Course({
       <AlertList topic="sequence" />
       <Sequence
         unitId={unitId}
+        sectionId={section ? section.id : null}
         sequenceId={sequenceId}
         courseId={courseId}
         unitNavigationHandler={unitNavigationHandler}

src/courseware/course/sequence/InContextSidebar.jsx

@@ -0,0 +1,96 @@
+import React, { useState } from 'react';
+
+import PropTypes from 'prop-types';
+import { Button, Form } from '@edx/paragon';
+import { getConfig } from '@edx/frontend-platform';
+
+import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
+import { faPlug } from '@fortawesome/free-solid-svg-icons';
+import PluginComponent from '../../../plugin-test/PluginComponent';
+import { useModel, useModels } from '../../../generic/model-store';
+import { loadDynamicScript, loadScriptComponent } from '../../../plugin-test/utils';
+
+export default function InContextSidebar({
+  courseId, sectionId, unitId, sequenceId,
+}) {
+  const course = useModel('coursewareMeta', courseId);
+  const section = useModel('sections', sectionId);
+  const unit = useModel('units', unitId);
+  const sequence = useModel('sequences', sequenceId);
+
+  const sections = useModels('sections', course ? course.sectionIds : []);
+  let sequenceIds = [];
+  if (sections) {
+    sections.forEach((curSection) => {
+      sequenceIds = sequenceIds.concat(curSection.sequenceIds);
+    });
+  }
+  const sequences = useModels('sequences', sequenceIds);
+  let unitIds = [];
+  if (sequences) {
+    sequences.forEach((curSequence) => {
+      unitIds = unitIds.concat(curSequence.unitIds);
+    });
+  }
+  const units = useModels('units', unitIds);
+
+  const [pluginUrl, setPluginUrl] = useState('');
+  const handlePluginUrlChange = (event) => {
+    setPluginUrl(event.target.value);
+  };
+
+  const handlePluginAdd = (event) => {
+    event.preventDefault();
+    loadDynamicScript(pluginUrl).then(() => {
+      const pluginFunction = loadScriptComponent('plugin', './Pomodoro');
+      pluginFunction();
+      setPluginUrl('');
+    });
+  };
+
+  if (!course || !section || !unit || !sequence) {
+    return null;
+  }
+  return (
+    <div className="pt-3">
+      <div className="mb-3">
+        <Form onSubmit={handlePluginAdd}>
+          <h4><FontAwesomeIcon icon={faPlug} /> Add a plugin?</h4>
+          <Form.Control className="mb-1" onChange={handlePluginUrlChange} placeholder="URL to your plugin..." type="text" />
+          <Button type="submit">Add</Button>
+        </Form>
+      </div>
+      <hr />
+      {getConfig().plugins.slots.coursewareSidebar.map((plugin) => (
+        <React.Fragment key={`plugin-${plugin.url}-${plugin.module}`}>
+          <PluginComponent
+            course={course}
+            activeUnit={unit}
+            activeSequence={sequence}
+            activeSection={section}
+            unitIds={unitIds}
+            units={units}
+            sequences={sequences}
+            sections={sections}
+            plugin={plugin}
+          />
+          <hr />
+        </React.Fragment>
+      ))}
+    </div>
+  );
+}
+
+InContextSidebar.propTypes = {
+  courseId: PropTypes.string,
+  sectionId: PropTypes.string,
+  unitId: PropTypes.string,
+  sequenceId: PropTypes.string,
+};
+
+InContextSidebar.defaultProps = {
+  courseId: null,
+  sectionId: null,
+  unitId: null,
+  sequenceId: null,
+};

src/courseware/course/sequence/Sequence.jsx

@@ -15,6 +15,7 @@ import { history } from '@edx/frontend-platform';
 import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
 import { faChevronLeft } from '@fortawesome/free-solid-svg-icons';
 
+import { Col, Container, Row } from '@edx/paragon';
 import PageLoading from '../../../generic/PageLoading';
 import { UserMessagesContext, ALERT_TYPES } from '../../../generic/user-messages';
 import { useModel } from '../../../generic/model-store';
@@ -23,6 +24,7 @@ import CourseLicense from '../course-license';
 import messages from './messages';
 import { SequenceNavigation, UnitNavigation } from './sequence-navigation';
 import SequenceContent from './SequenceContent';
+import InContextSidebar from './InContextSidebar';
 
 function REV1512Flyover({ toggleREV1512Flyover }) {
   // This component should be reverted after the REV1512 experiment
@@ -183,6 +185,7 @@ REV1512FlyoverMobile.propTypes = {
 
 function Sequence({
   unitId,
+  sectionId,
   sequenceId,
   courseId,
   unitNavigationHandler,
@@ -309,61 +312,74 @@ function Sequence({
   if (sequenceStatus === 'loaded') {
     return (
       <div>
-        <div className="sequence-container" style={{ display: 'inline-flex', flexDirection: 'row' }}>
-          <div className="sequence" style={{ width: '100%' }}>
-            <SequenceNavigation
-              sequenceId={sequenceId}
-              unitId={unitId}
-              className="mb-4"
-              toggleREV1512Flyover={toggleREV1512Flyover} /* This line should be reverted after REV1512 experiment */
-              REV1512FlyoverEnabled={REV1512FlyoverEnabled} /* This line should be reverted after REV1512 experiment */
-              isREV1512FlyoverVisible={isREV1512FlyoverVisible} /* should be reverted after REV1512 experiment */
-              nextSequenceHandler={() => {
-                logEvent('edx.ui.lms.sequence.next_selected', 'top');
-                handleNext();
-              }}
-              onNavigate={(destinationUnitId) => {
-                logEvent('edx.ui.lms.sequence.tab_selected', 'top', destinationUnitId);
-                handleNavigate(destinationUnitId);
-              }}
-              previousSequenceHandler={() => {
-                logEvent('edx.ui.lms.sequence.previous_selected', 'top');
-                handlePrevious();
-              }}
-              goToCourseExitPage={() => goToCourseExitPage()}
-            />
-            <div className="unit-container flex-grow-1">
-              <SequenceContent
-                courseId={courseId}
-                gated={gated}
+        <Container className="sequence-container px-3">
+          <Row>
+            <Col sm={8} xs={12} className="sequence px-0">
+              <SequenceNavigation
                 sequenceId={sequenceId}
                 unitId={unitId}
-                unitLoadedHandler={handleUnitLoaded}
-              />
-              {unitHasLoaded && (
-              <UnitNavigation
-                sequenceId={sequenceId}
-                unitId={unitId}
-                onClickPrevious={() => {
-                  logEvent('edx.ui.lms.sequence.previous_selected', 'bottom');
-                  handlePrevious();
-                }}
-                onClickNext={() => {
-                  logEvent('edx.ui.lms.sequence.next_selected', 'bottom');
+                className="mb-4"
+                /* This line should be reverted after REV1512 experiment */
+                toggleREV1512Flyover={toggleREV1512Flyover}
+                /* This line should be reverted after REV1512 experiment */
+                REV1512FlyoverEnabled={REV1512FlyoverEnabled}
+                /* should be reverted after REV1512 experiment */
+                isREV1512FlyoverVisible={isREV1512FlyoverVisible}
+                nextSequenceHandler={() => {
+                  logEvent('edx.ui.lms.sequence.next_selected', 'top');
                   handleNext();
                 }}
+                onNavigate={(destinationUnitId) => {
+                  logEvent('edx.ui.lms.sequence.tab_selected', 'top', destinationUnitId);
+                  handleNavigate(destinationUnitId);
+                }}
+                previousSequenceHandler={() => {
+                  logEvent('edx.ui.lms.sequence.previous_selected', 'top');
+                  handlePrevious();
+                }}
                 goToCourseExitPage={() => goToCourseExitPage()}
               />
-              )}
-            </div>
-          </div>
-          {/* This block of code should be reverted post REV1512 experiment */}
-          {REV1512FlyoverEnabled && isREV1512FlyoverVisible() && (
-            isMobile
-              ? <REV1512FlyoverMobile toggleREV1512Flyover={toggleREV1512Flyover} />
-              : <REV1512Flyover toggleREV1512Flyover={toggleREV1512Flyover} />
-          )}
-        </div>
+              <div className="unit-container flex-grow-1">
+                <SequenceContent
+                  courseId={courseId}
+                  gated={gated}
+                  sequenceId={sequenceId}
+                  unitId={unitId}
+                  unitLoadedHandler={handleUnitLoaded}
+                />
+                {unitHasLoaded && (
+                <UnitNavigation
+                  sequenceId={sequenceId}
+                  unitId={unitId}
+                  onClickPrevious={() => {
+                    logEvent('edx.ui.lms.sequence.previous_selected', 'bottom');
+                    handlePrevious();
+                  }}
+                  onClickNext={() => {
+                    logEvent('edx.ui.lms.sequence.next_selected', 'bottom');
+                    handleNext();
+                  }}
+                  goToCourseExitPage={() => goToCourseExitPage()}
+                />
+                )}
+              </div>
+            </Col>
+            <Col className="ml-3 sequence">
+              <InContextSidebar
+                courseId={courseId}
+                sectionId={sectionId}
+                sequenceId={sequenceId}
+                unitId={unitId}
+              />
+            </Col>
+            {/* This block of code should be reverted post REV1512 experiment */}
+            {REV1512FlyoverEnabled && isREV1512FlyoverVisible() && (
+              isMobile
+                ? <REV1512FlyoverMobile toggleREV1512Flyover={toggleREV1512Flyover} />
+                : <REV1512Flyover toggleREV1512Flyover={toggleREV1512Flyover} />
+            )}
+          </Row>
+        </Container>
         <CourseLicense license={course.license || undefined} />
       </div>
     );
@@ -380,6 +396,7 @@ function Sequence({
 Sequence.propTypes = {
   unitId: PropTypes.string,
   sequenceId: PropTypes.string,
+  sectionId: PropTypes.string,
   courseId: PropTypes.string.isRequired,
   unitNavigationHandler: PropTypes.func.isRequired,
   nextSequenceHandler: PropTypes.func.isRequired,
@@ -392,6 +409,7 @@ Sequence.propTypes = {
 
 Sequence.defaultProps = {
   sequenceId: null,
+  sectionId: null,
   unitId: null,
 };
 

src/index.jsx

@@ -4,11 +4,12 @@ import 'regenerator-runtime/runtime';
 import {
   APP_INIT_ERROR, APP_READY, subscribe, initialize,
   mergeConfig,
+  getConfig,
 } from '@edx/frontend-platform';
 import { AppProvider, ErrorPage, PageRoute } from '@edx/frontend-platform/react';
 import React from 'react';
 import ReactDOM from 'react-dom';
-import { Switch } from 'react-router-dom';
+import { Route, Switch } from 'react-router-dom';
 
 import Footer, { messages as footerMessages } from '@edx/frontend-component-footer';
 
@@ -27,12 +28,16 @@ import { TabContainer } from './tab-page';
 import { fetchDatesTab, fetchOutlineTab, fetchProgressTab } from './course-home/data';
 import { fetchCourse } from './courseware/data';
 import initializeStore from './store';
+import PluginTestPage from './plugin-test/PluginTestPage';
+import { COMPONENT } from './plugin-test/PluginComponent';
+import { loadDynamicScript, loadScriptComponent } from './plugin-test/utils';
 
 subscribe(APP_READY, () => {
   ReactDOM.render(
     <AppProvider store={initializeStore()}>
       <UserMessagesProvider>
         <Switch>
+          <Route exact path="/" component={PluginTestPage} />
           <PageRoute path="/redirect" component={CoursewareRedirectLandingPage} />
           <PageRoute path="/course/:courseId/home">
             <TabContainer tab="outline" fetch={fetchOutlineTab} slice="courseHome">
@@ -68,6 +73,13 @@ subscribe(APP_READY, () => {
     </AppProvider>,
     document.getElementById('root'),
   );
+
+  getConfig().plugins.scripts.forEach((plugin) => {
+    loadDynamicScript(plugin.url).then(() => {
+      const pluginFunction = loadScriptComponent(plugin.scope, plugin.module);
+      pluginFunction();
+    });
+  });
 });
 
 subscribe(APP_INIT_ERROR, (error) => {
@@ -90,6 +102,43 @@ initialize({
         SUPPORT_URL_VERIFIED_CERTIFICATE: process.env.SUPPORT_URL_VERIFIED_CERTIFICATE || null,
         TWITTER_HASHTAG: process.env.TWITTER_HASHTAG || null,
         TWITTER_URL: process.env.TWITTER_URL || null,
+        plugins: {
+          scripts: [
+            // {
+            //   url: 'http://localhost:7331/remoteEntry.js',
+            //   scope: 'plugin',
+            //   module: './Pomodoro',
+            //   type: SCRIPT,
+            // },
+          ],
+          slots: {
+            header: [
+              {
+                url: 'http://localhost:7331/remoteEntry.js',
+                scope: 'plugin',
+                module: './Banner',
+                type: COMPONENT,
+              },
+            ],
+            coursewareSidebar: [
+              {
+                url: 'http://localhost:7331/remoteEntry.js',
+                scope: 'plugin',
+                module: './Discussions',
+                type: COMPONENT,
+              },
+              {
+                url: 'http://localhost:7331/remoteEntry.js',
+                scope: 'plugin',
+                module: './Calendly',
+                type: COMPONENT,
+                props: {
+                  username: 'djoy',
+                },
+              },
+            ],
+          },
+        },
       }, 'LearnerAppConfig');
     },
   },

src/index.scss

@@ -95,8 +95,6 @@
 }
 
 .sequence-container {
-  display: flex;
-  flex-direction: column;
   flex-grow: 1;
   margin-bottom: 4rem;
 
@@ -111,6 +109,7 @@
 }
 
 .sequence {
+  width: 100%;
   @media (min-width: map-get($grid-breakpoints, 'sm')) {
     border: solid 1px #EAEAEA;
     border-radius: 4px;
@@ -302,9 +301,9 @@
 .unit-iframe-wrapper {
   margin: 0 -20px 2rem;
 
-  @media (min-width: 830px) {
-    margin: 0 -40px 2rem;
-  }
+  // @media (min-width: 830px) {
+  //   margin: 0 -20px 2rem;
+  // }
 }
 
 #unit-iframe {

src/plugin-test/PluginComponent.jsx

@@ -0,0 +1,105 @@
+import React, { Suspense } from 'react';
+import PropTypes from 'prop-types';
+import { injectIntl, intlShape } from '@edx/frontend-platform/i18n';
+import PageLoading from '../generic/PageLoading';
+
+import messages from './messages';
+import { loadDynamicScript, loadScriptComponent } from './utils';
+import PluginErrorBoundary from './PluginErrorBoundary';
+
+// These are intended to represent three different plugin types.  They're not fully used yet.
+// Different plugins of different types would have different loading functionality.
+export const COMPONENT = 'component'; // loads JS script then loads react component from its exports
+export const SCRIPT = 'script'; // loads JS script
+export const IFRAME = 'iframe'; // loads iframe at the URL, rather than loading a JS file.
+export const LTI = 'lti'; // loads LTI iframe at the URL, rather than loading a JS file.
+
+const useDynamicScript = (url) => {
+  const [ready, setReady] = React.useState(false);
+  const [failed, setFailed] = React.useState(false);
+  // eslint-disable-next-line no-unused-vars
+  const [element, setElement] = React.useState(null);
+  React.useEffect(() => {
+    if (!url) {
+      return () => {};
+    }
+
+    setReady(false);
+    setFailed(false);
+
+    loadDynamicScript(url).then((el) => {
+      setElement(el);
+      setReady(true);
+    }).catch(() => {
+      setReady(false);
+      setFailed(true);
+    });
+
+    return () => {
+      // TODO: How to do reference checking on this script to only remove it when the last
+      // component using it has unmounted?
+      // document.head.removeChild(element);
+    };
+  }, [url]);
+
+  return {
+    ready,
+    failed,
+  };
+};
+
+function PluginComponent({ plugin, intl, ...props }) {
+  const url = plugin ? plugin.url : null;
+  const { ready, failed } = useDynamicScript(url);
+
+  if (!plugin) {
+    return null;
+  }
+
+  if (!ready) {
+    return (
+      <PageLoading
+        srMessage={intl.formatMessage(messages.loading)}
+      />
+    );
+  }
+
+  if (failed) {
+    return null;
+  }
+
+  const Component = React.lazy(
+    loadScriptComponent(plugin.scope, plugin.module),
+  );
+
+  return (
+    <Suspense
+      fallback={(
+        <PageLoading
+          srMessage={intl.formatMessage(messages.loading)}
+        />
+      )}
+    >
+      <PluginErrorBoundary>
+        <Component {...props} {...plugin.props} />
+      </PluginErrorBoundary>
+    </Suspense>
+  );
+}
+
+PluginComponent.propTypes = {
+  plugin: PropTypes.shape({
+    scope: PropTypes.string.isRequired,
+    module: PropTypes.string.isRequired,
+    url: PropTypes.string.isRequired,
+    type: PropTypes.oneOf([COMPONENT, SCRIPT, IFRAME]).isRequired,
+    props: PropTypes.object,
+  }),
+  intl: intlShape.isRequired,
+};
+
+PluginComponent.defaultProps = {
+  plugin: null,
+};
+
+export default injectIntl(PluginComponent);

src/plugin-test/PluginErrorBoundary.jsx

@@ -0,0 +1,36 @@
+import React, { Component } from 'react';
+import PropTypes from 'prop-types';
+
+export default class PluginErrorBoundary extends Component {
+  constructor(props) {
+    super(props);
+    this.state = { hasError: false };
+  }
+
+  static getDerivedStateFromError() {
+    // Update state so the next render will show the fallback UI.
+    return { hasError: true };
+  }
+
+  componentDidCatch(error, errorInfo) {
+    // eslint-disable-next-line no-console
+    console.error(error, errorInfo);
+  }
+
+  render() {
+    if (this.state.hasError) {
+      // You can render any custom fallback UI
+      return <div>Plugin failed to load.</div>;
+    }
+
+    return this.props.children;
+  }
+}
+
+PluginErrorBoundary.propTypes = {
+  children: PropTypes.node,
+};
+
+PluginErrorBoundary.defaultProps = {
+  children: null,
+};

src/plugin-test/PluginTestPage.jsx

@@ -0,0 +1,30 @@
+import React from 'react';
+
+import { getConfig } from '@edx/frontend-platform';
+import PluginComponent from './PluginComponent';
+
+function PluginTestPage() {
+  return (
+    <div>
+      <h1>Dynamic Plugin Host</h1>
+      <h2>App 1</h2>
+      <p>
+        The Dynamic Plugin will take advantage Module Federation{' '}
+        <strong>remotes</strong> and <strong>exposes</strong>. It will no load
+        components that have been loaded already.
+      </p>
+      {/* <Button className="mr-3" onClick={setPluginOne}>Load Plugin One</Button>
+      <Button onClick={setPluginTwo}>Load Plugin Two</Button> */}
+      <div style={{ marginTop: '2em' }}>
+        {getConfig().plugins.slots.testPage.map((plugin) => (
+          <PluginComponent
+            key={`plugin-${plugin.url}-${plugin.module}`}
+            plugin={plugin}
+          />
+        ))}
+      </div>
+    </div>
+  );
+}
+
+export default PluginTestPage;

src/plugin-test/messages.js

@@ -0,0 +1,11 @@
+import { defineMessages } from '@edx/frontend-platform/i18n';
+
+const messages = defineMessages({
+  loading: {
+    id: 'plugin.loading',
+    defaultMessage: 'Loading',
+    description: 'Message shown to screen readers while a plugin is loading.',
+  },
+});
+
+export default messages;

src/plugin-test/utils.js

@@ -0,0 +1,37 @@
+export function loadDynamicScript(url) {
+  return new Promise((resolve, reject) => {
+    const element = document.createElement('script');
+
+    element.src = url;
+    element.type = 'text/javascript';
+    element.async = true;
+
+    element.onload = () => {
+      // eslint-disable-next-line no-console
+      console.log(`Dynamic Script Loaded: ${url}`);
+      resolve(element, url);
+    };
+
+    element.onerror = () => {
+      reject(new Error(`Failed to load dynamic script with URL: ${url}`));
+    };
+
+    document.head.appendChild(element);
+  });
+}
+
+export function loadScriptComponent(scope, module) {
+  return async () => {
+    // Initializes the share scope. This fills it with known provided modules from this build and all remotes
+    // eslint-disable-next-line no-undef
+    await __webpack_init_sharing__('default');
+
+    const container = window[scope]; // or get the container somewhere else
+    // Initialize the container, it may provide shared modules
+    // eslint-disable-next-line no-undef
+    await container.init(__webpack_share_scopes__.default);
+    const factory = await window[scope].get(module);
+    const Module = factory();
+    return Module;
+  };
+}

src/tab-page/LoadedTabPage.jsx

@@ -10,6 +10,7 @@ import { AlertList } from '../generic/user-messages';
 import InstructorToolbar from '../instructor-toolbar';
 import useEnrollmentAlert from '../alerts/enrollment-alert';
 import useLogistrationAlert from '../alerts/logistration-alert';
+import PluginComponent from '../plugin-test/PluginComponent';
 
 function LoadedTabPage({
   activeTabSlug,
@@ -38,6 +39,12 @@ function LoadedTabPage({
       <Helmet>
         <title>{`${activeTab.title} | ${title} | ${getConfig().SITE_NAME}`}</title>
       </Helmet>
+      {getConfig().plugins.slots.header.map((plugin) => (
+        <PluginComponent
+          key={`plugin-${plugin.url}-${plugin.module}`}
+          plugin={plugin}
+        />
+      ))}
       <Header
         courseOrg={org}
         courseNumber={number}
@@ -49,6 +56,7 @@ function LoadedTabPage({
           unitId={unitId}
         />
       )}
+
       <main id="main-content" className="d-flex flex-column flex-grow-1">
         <AlertList
           topic="outline"

webpack.dev.config.js

@@ -0,0 +1,28 @@
+const { createConfig } = require('@edx/frontend-build');
+// eslint-disable-next-line import/no-extraneous-dependencies
+const { ModuleFederationPlugin } = require('webpack').container;
+
+module.exports = createConfig('webpack-dev', {
+  plugins: [
+    new ModuleFederationPlugin({
+      name: 'learning',
+      shared: {
+        react: {
+          import: 'react', // the "react" package will be used a provided and fallback module
+          shareKey: 'react', // under this name the shared module will be placed in the share scope
+          shareScope: 'default', // share scope with this name will be used
+          singleton: true, // only a single version of the shared module is allowed
+          eager: true,
+        },
+        'react-dom': {
+          singleton: true, // only a single version of the shared module is allowed
+          eager: true,
+        },
+        '@edx/frontend-platform': {
+          singleton: true,
+          eager: true,
+        },
+      },
+    }),
+  ],
+});