Fix some React warnings

app/javascript/flavours/glitch/components/intersection_observer_article.js

@@ -119,7 +119,7 @@ export default class IntersectionObserverArticle extends ImmutablePureComponent
         data-id={id}
         tabIndex='0'
         style={style}>
-          {children && React.cloneElement(children, { hidden: !isIntersecting && (isHidden || cachedHeight) })}
+          {children && React.cloneElement(children, { hidden: !isIntersecting && (isHidden || !!cachedHeight) })}
       </article>
     );
   }

app/javascript/flavours/glitch/components/status_action_bar.js

@@ -284,11 +284,11 @@ export default class StatusActionBar extends ImmutablePureComponent {
       <div className='status__action-bar'>
         {replyButton}
         {!directMessage && [
-          <IconButton className='status__action-bar-button' disabled={reblogDisabled} active={status.get('reblogged')} pressed={status.get('reblogged')} title={reblogDisabled ? intl.formatMessage(messages.cannot_reblog) : intl.formatMessage(reblogMessage)} icon={reblogIcon} onClick={this.handleReblogClick} />,
+          <IconButton key='reblog-button' className='status__action-bar-button' disabled={reblogDisabled} active={status.get('reblogged')} pressed={status.get('reblogged')} title={reblogDisabled ? intl.formatMessage(messages.cannot_reblog) : intl.formatMessage(reblogMessage)} icon={reblogIcon} onClick={this.handleReblogClick} />,
-          <IconButton className='status__action-bar-button star-icon' animate active={status.get('favourited')} pressed={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} />,
+          <IconButton key='favourite-button' className='status__action-bar-button star-icon' animate active={status.get('favourited')} pressed={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} />,
           shareButton,
-          <IconButton className='status__action-bar-button bookmark-icon' disabled={anonymousAccess} active={status.get('bookmarked')} pressed={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} />,
+          <IconButton key='bookmark-button' className='status__action-bar-button bookmark-icon' disabled={anonymousAccess} active={status.get('bookmarked')} pressed={status.get('bookmarked')} title={intl.formatMessage(messages.bookmark)} icon='bookmark' onClick={this.handleBookmarkClick} />,
-          <div className='status__action-bar-dropdown'>
+          <div key='dropdown-button' className='status__action-bar-dropdown'>
             <DropdownMenuContainer disabled={anonymousAccess} status={status} items={menu} icon='ellipsis-h' size={18} direction='right' ariaLabel={intl.formatMessage(messages.more)} />
           </div>,
         ]}

app/javascript/flavours/glitch/features/local_settings/page/item/index.js

@@ -8,7 +8,7 @@ import ImmutablePropTypes from 'react-immutable-proptypes';
 export default class LocalSettingsPageItem extends React.PureComponent {
 
   static propTypes = {
-    children: PropTypes.element.isRequired,
+    children: PropTypes.node.isRequired,
     dependsOn: PropTypes.array,
     dependsOnNot: PropTypes.array,
     id: PropTypes.string.isRequired,
@@ -63,12 +63,12 @@ export default class LocalSettingsPageItem extends React.PureComponent {
               disabled={!enabled}
             />
             {opt.message}
-            {opt.hint && <span class='hint'>{opt.hint}</span>}
+            {opt.hint && <span className='hint'>{opt.hint}</span>}
           </label>
         );
       });
       return (
-        <div class='glitch local-settings__page__item radio_buttons'>
+        <div className='glitch local-settings__page__item radio_buttons'>
           <fieldset>
             <legend>{children}</legend>
             {optionElems}