feat(status_action_bar): Web share button (#4365)

app/javascript/mastodon/components/status_action_bar.js

@@ -12,6 +12,7 @@ const messages = defineMessages({
   mute: { id: 'account.mute', defaultMessage: 'Mute @{name}' },
   block: { id: 'account.block', defaultMessage: 'Block @{name}' },
   reply: { id: 'status.reply', defaultMessage: 'Reply' },
+  share: { id: 'status.share', defaultMessage: 'Share' },
   replyAll: { id: 'status.replyAll', defaultMessage: 'Reply to thread' },
   reblog: { id: 'status.reblog', defaultMessage: 'Boost' },
   cannot_reblog: { id: 'status.cannot_reblog', defaultMessage: 'This post cannot be boosted' },
@@ -57,6 +58,13 @@ export default class StatusActionBar extends ImmutablePureComponent {
     this.props.onReply(this.props.status, this.context.router.history);
   }
 
+  handleShareClick = () => {
+    navigator.share({
+      text: this.props.status.get('search_index'),
+      url: this.props.status.get('url'),
+    });
+  }
+
   handleFavouriteClick = () => {
     this.props.onFavourite(this.props.status);
   }
@@ -136,11 +144,16 @@ export default class StatusActionBar extends ImmutablePureComponent {
       replyTitle = intl.formatMessage(messages.replyAll);
     }
 
+    const shareButton = ('share' in navigator) && status.get('visibility') === 'public' && (
+      <IconButton className='status__action-bar-button' title={intl.formatMessage(messages.share)} icon='share-alt' onClick={this.handleShareClick} />
+    );
+
     return (
       <div className='status__action-bar'>
         <IconButton className='status__action-bar-button' disabled={anonymousAccess} title={replyTitle} icon={replyIcon} onClick={this.handleReplyClick} />
         <IconButton className='status__action-bar-button' disabled={anonymousAccess || reblogDisabled} active={status.get('reblogged')} title={reblogDisabled ? intl.formatMessage(messages.cannot_reblog) : intl.formatMessage(messages.reblog)} icon={reblogIcon} onClick={this.handleReblogClick} />
         <IconButton className='status__action-bar-button star-icon' disabled={anonymousAccess} animate active={status.get('favourited')} title={intl.formatMessage(messages.favourite)} icon='star' onClick={this.handleFavouriteClick} />
+        {shareButton}
 
         <div className='status__action-bar-dropdown'>
           <DropdownMenu disabled={anonymousAccess} items={menu} icon='ellipsis-h' size={18} direction='right' ariaLabel='More' />