Lazy load components (#3879)

* feat: Lazy-load routes

* feat: Lazy-load modals

* feat: Lazy-load columns

* refactor: Simplify Bundle API

* feat: Optimize bundles

* feat: Prevent flashing the waiting state

* feat: Preload commonly used bundles

* feat: Lazy load Compose reducers

* feat: Lazy load Notifications reducer

* refactor: Move all dynamic imports into one file

* fix: Minor bugs

* fix: Manually hydrate the lazy-loaded reducers

* refactor: Move all dynamic imports to async-components

* fix: Loading modal style

* refactor: Avoid converting the raw state for each lazy hydration

* refactor: Remove unused component

* refactor: Maintain modal name

* fix: Add as=script to preload link

* chore: Fix lint error

* fix(components/bundle): Check if timestamp is set when computing elapsed

* fix: Load compose reducers for the onboarding modal

app/javascript/mastodon/features/ui/components/bundle.js

@@ -0,0 +1,96 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+const emptyComponent = () => null;
+const noop = () => { };
+
+class Bundle extends React.Component {
+
+  static propTypes = {
+    fetchComponent: PropTypes.func.isRequired,
+    loading: PropTypes.func,
+    error: PropTypes.func,
+    children: PropTypes.func.isRequired,
+    renderDelay: PropTypes.number,
+    onRender: PropTypes.func,
+    onFetch: PropTypes.func,
+    onFetchSuccess: PropTypes.func,
+    onFetchFail: PropTypes.func,
+  }
+
+  static defaultProps = {
+    loading: emptyComponent,
+    error: emptyComponent,
+    renderDelay: 0,
+    onRender: noop,
+    onFetch: noop,
+    onFetchSuccess: noop,
+    onFetchFail: noop,
+  }
+
+  state = {
+    mod: undefined,
+    forceRender: false,
+  }
+
+  componentWillMount() {
+    this.load(this.props);
+  }
+
+  componentWillReceiveProps(nextProps) {
+    if (nextProps.fetchComponent !== this.props.fetchComponent) {
+      this.load(nextProps);
+    }
+  }
+
+  componentDidUpdate () {
+    this.props.onRender();
+  }
+
+  componentWillUnmount () {
+    if (this.timeout) {
+      clearTimeout(this.timeout);
+    }
+  }
+
+  load = (props) => {
+    const { fetchComponent, onFetch, onFetchSuccess, onFetchFail, renderDelay } = props || this.props;
+
+    this.setState({ mod: undefined });
+    onFetch();
+
+    if (renderDelay !== 0) {
+      this.timestamp = new Date();
+      this.timeout = setTimeout(() => this.setState({ forceRender: true }), renderDelay);
+    }
+
+    return fetchComponent()
+      .then((mod) => {
+        this.setState({ mod: mod.default });
+        onFetchSuccess();
+      })
+      .catch((error) => {
+        this.setState({ mod: null });
+        onFetchFail(error);
+      });
+  }
+
+  render() {
+    const { loading: Loading, error: Error, children, renderDelay } = this.props;
+    const { mod, forceRender } = this.state;
+    const elapsed = this.timestamp ? (new Date() - this.timestamp) : renderDelay;
+
+    if (mod === undefined) {
+      return (elapsed >= renderDelay || forceRender) ? <Loading /> : null;
+    }
+
+    if (mod === null) {
+      return <Error onRetry={this.load} />;
+    }
+
+    return children(mod);
+  }
+
+}
+
+export default Bundle;

app/javascript/mastodon/features/ui/components/bundle_column_error.js

@@ -0,0 +1,44 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import { defineMessages, injectIntl } from 'react-intl';
+
+import Column from './column';
+import ColumnHeader from './column_header';
+import ColumnBackButtonSlim from '../../../components/column_back_button_slim';
+import IconButton from '../../../components/icon_button';
+
+const messages = defineMessages({
+  title: { id: 'bundle_column_error.title', defaultMessage: 'Network error' },
+  body: { id: 'bundle_column_error.body', defaultMessage: 'Something went wrong while loading this component.' },
+  retry: { id: 'bundle_column_error.retry', defaultMessage: 'Try again' },
+});
+
+class BundleColumnError extends React.Component {
+
+  static propTypes = {
+    onRetry: PropTypes.func.isRequired,
+    intl: PropTypes.object.isRequired,
+  }
+
+  handleRetry = () => {
+    this.props.onRetry();
+  }
+
+  render () {
+    const { intl: { formatMessage } } = this.props;
+
+    return (
+      <Column>
+        <ColumnHeader icon='exclamation-circle' type={formatMessage(messages.title)} />
+        <ColumnBackButtonSlim />
+        <div className='error-column'>
+          <IconButton title={formatMessage(messages.retry)} icon='refresh' onClick={this.handleRetry} size={64} />
+          {formatMessage(messages.body)}
+        </div>
+      </Column>
+    );
+  }
+
+}
+
+export default injectIntl(BundleColumnError);

app/javascript/mastodon/features/ui/components/bundle_modal_error.js

@@ -0,0 +1,53 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import { defineMessages, injectIntl } from 'react-intl';
+
+import IconButton from '../../../components/icon_button';
+
+const messages = defineMessages({
+  error: { id: 'bundle_modal_error.message', defaultMessage: 'Something went wrong while loading this component.' },
+  retry: { id: 'bundle_modal_error.retry', defaultMessage: 'Try again' },
+  close: { id: 'bundle_modal_error.close', defaultMessage: 'Close' },
+});
+
+class BundleModalError extends React.Component {
+
+  static propTypes = {
+    onRetry: PropTypes.func.isRequired,
+    onClose: PropTypes.func.isRequired,
+    intl: PropTypes.object.isRequired,
+  }
+
+  handleRetry = () => {
+    this.props.onRetry();
+  }
+
+  render () {
+    const { onClose, intl: { formatMessage } } = this.props;
+
+    // Keep the markup in sync with <ModalLoading />
+    // (make sure they have the same dimensions)
+    return (
+      <div className='modal-root__modal error-modal'>
+        <div className='error-modal__body'>
+          <IconButton title={formatMessage(messages.retry)} icon='refresh' onClick={this.handleRetry} size={64} />
+          {formatMessage(messages.error)}
+        </div>
+
+        <div className='error-modal__footer'>
+          <div>
+            <button
+              onClick={onClose}
+              className='error-modal__nav onboarding-modal__skip'
+            >
+              {formatMessage(messages.close)}
+            </button>
+          </div>
+        </div>
+      </div>
+    );
+  }
+
+}
+
+export default injectIntl(BundleModalError);

app/javascript/mastodon/features/ui/components/column_loading.js

@@ -0,0 +1,13 @@
+import React from 'react';
+
+import Column from '../../../components/column';
+import ColumnHeader from '../../../components/column_header';
+
+const ColumnLoading = () => (
+  <Column>
+    <ColumnHeader icon=' ' title='' multiColumn={false} />
+    <div className='scrollable' />
+  </Column>
+);
+
+export default ColumnLoading;

app/javascript/mastodon/features/ui/components/columns_area.js

@@ -2,15 +2,15 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import ImmutablePropTypes from 'react-immutable-proptypes';
 import ImmutablePureComponent from 'react-immutable-pure-component';
+
 import ReactSwipeable from 'react-swipeable';
-import HomeTimeline from '../../home_timeline';
-import Notifications from '../../notifications';
-import PublicTimeline from '../../public_timeline';
-import CommunityTimeline from '../../community_timeline';
-import HashtagTimeline from '../../hashtag_timeline';
-import Compose from '../../compose';
 import { getPreviousLink, getNextLink } from './tabs_bar';
 
+import BundleContainer from '../containers/bundle_container';
+import ColumnLoading from './column_loading';
+import BundleColumnError from './bundle_column_error';
+import { Compose, Notifications, HomeTimeline, CommunityTimeline, PublicTimeline, HashtagTimeline } from '../../ui/util/async-components';
+
 const componentMap = {
   'COMPOSE': Compose,
   'HOME': HomeTimeline,
@@ -48,6 +48,14 @@ export default class ColumnsArea extends ImmutablePureComponent {
     }
   };
 
+  renderLoading = () => {
+    return <ColumnLoading />;
+  }
+
+  renderError = (props) => {
+    return <BundleColumnError {...props} />;
+  }
+
   render () {
     const { columns, children, singleColumn } = this.props;
 
@@ -62,9 +70,13 @@ export default class ColumnsArea extends ImmutablePureComponent {
     return (
       <div className='columns-area'>
         {columns.map(column => {
-          const SpecificComponent = componentMap[column.get('id')];
           const params = column.get('params', null) === null ? null : column.get('params').toJS();
-          return <SpecificComponent key={column.get('uuid')} columnId={column.get('uuid')} params={params} multiColumn />;
+
+          return (
+            <BundleContainer key={column.get('uuid')} fetchComponent={componentMap[column.get('id')]} loading={this.renderLoading} error={this.renderError}>
+              {SpecificComponent => <SpecificComponent columnId={column.get('uuid')} params={params} multiColumn />}
+            </BundleContainer>
+          );
         })}
 
         {React.Children.map(children, child => React.cloneElement(child, { multiColumn: true }))}

app/javascript/mastodon/features/ui/components/modal_loading.js

@@ -0,0 +1,20 @@
+import React from 'react';
+
+import LoadingIndicator from '../../../components/loading_indicator';
+
+// Keep the markup in sync with <BundleModalError />
+// (make sure they have the same dimensions)
+const ModalLoading = () => (
+  <div className='modal-root__modal error-modal'>
+    <div className='error-modal__body'>
+      <LoadingIndicator />
+    </div>
+    <div className='error-modal__footer'>
+      <div>
+        <button className='error-modal__nav onboarding-modal__skip' />
+      </div>
+    </div>
+  </div>
+);
+
+export default ModalLoading;

app/javascript/mastodon/features/ui/components/modal_root.js

@@ -1,13 +1,18 @@
 import React from 'react';
 import PropTypes from 'prop-types';
-import MediaModal from './media_modal';
-import OnboardingModal from './onboarding_modal';
-import VideoModal from './video_modal';
-import BoostModal from './boost_modal';
-import ConfirmationModal from './confirmation_modal';
-import ReportModal from './report_modal';
 import TransitionMotion from 'react-motion/lib/TransitionMotion';
 import spring from 'react-motion/lib/spring';
+import BundleContainer from '../containers/bundle_container';
+import BundleModalError from './bundle_modal_error';
+import ModalLoading from './modal_loading';
+import {
+  MediaModal,
+  OnboardingModal,
+  VideoModal,
+  BoostModal,
+  ConfirmationModal,
+  ReportModal,
+} from '../../../features/ui/util/async-components';
 
 const MODAL_COMPONENTS = {
   'MEDIA': MediaModal,
@@ -49,6 +54,22 @@ export default class ModalRoot extends React.PureComponent {
     return { opacity: spring(0), scale: spring(0.98) };
   }
 
+  renderModal = (SpecificComponent) => {
+    const { props, onClose } = this.props;
+
+    return <SpecificComponent {...props} onClose={onClose} />;
+  }
+
+  renderLoading = () => {
+    return <ModalLoading />;
+  }
+
+  renderError = (props) => {
+    const { onClose } = this.props;
+
+    return <BundleModalError {...props} onClose={onClose} />;
+  }
+
   render () {
     const { type, props, onClose } = this.props;
     const visible = !!type;
@@ -70,18 +91,14 @@ export default class ModalRoot extends React.PureComponent {
       >
         {interpolatedStyles =>
           <div className='modal-root'>
-            {interpolatedStyles.map(({ key, data: { type, props }, style }) => {
-              const SpecificComponent = MODAL_COMPONENTS[type];
-
-              return (
-                <div key={key} style={{ pointerEvents: visible ? 'auto' : 'none' }}>
-                  <div role='presentation' className='modal-root__overlay' style={{ opacity: style.opacity }} onClick={onClose} />
-                  <div className='modal-root__container' style={{ opacity: style.opacity, transform: `translateZ(0px) scale(${style.scale})` }}>
-                    <SpecificComponent {...props} onClose={onClose} />
-                  </div>
+            {interpolatedStyles.map(({ key, data: { type }, style }) => (
+              <div key={key} style={{ pointerEvents: visible ? 'auto' : 'none' }}>
+                <div role='presentation' className='modal-root__overlay' style={{ opacity: style.opacity }} onClick={onClose} />
+                <div className='modal-root__container' style={{ opacity: style.opacity, transform: `translateZ(0px) scale(${style.scale})` }}>
+                  <BundleContainer fetchComponent={MODAL_COMPONENTS[type]} loading={this.renderLoading} error={this.renderError} renderDelay={200}>{this.renderModal}</BundleContainer>
                 </div>
-              );
-            })}
+              </div>
+            ))}
           </div>
         }
       </TransitionMotion>