Change custom emoji to be animated when hovering container (#15637)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/mastodon/components/display_name.js

@@ -11,45 +11,30 @@ export default class DisplayName extends React.PureComponent {
     localDomain: PropTypes.string,
   };
 
-  _updateEmojis () {
-    const node = this.node;
-
-    if (!node || autoPlayGif) {
+  handleMouseEnter = ({ currentTarget }) => {
+    if (autoPlayGif) {
       return;
     }
 
-    const emojis = node.querySelectorAll('.custom-emoji');
+    const emojis = currentTarget.querySelectorAll('.custom-emoji');
 
     for (var i = 0; i < emojis.length; i++) {
       let emoji = emojis[i];
-      if (emoji.classList.contains('status-emoji')) {
-        continue;
-      }
-      emoji.classList.add('status-emoji');
-
-      emoji.addEventListener('mouseenter', this.handleEmojiMouseEnter, false);
-      emoji.addEventListener('mouseleave', this.handleEmojiMouseLeave, false);
+      emoji.src = emoji.getAttribute('data-original');
     }
   }
 
-  componentDidMount () {
-    this._updateEmojis();
-  }
+  handleMouseLeave = ({ currentTarget }) => {
+    if (autoPlayGif) {
+      return;
+    }
 
-  componentDidUpdate () {
-    this._updateEmojis();
-  }
+    const emojis = currentTarget.querySelectorAll('.custom-emoji');
 
-  handleEmojiMouseEnter = ({ target }) => {
-    target.src = target.getAttribute('data-original');
-  }
-
-  handleEmojiMouseLeave = ({ target }) => {
-    target.src = target.getAttribute('data-static');
-  }
-
-  setRef = (c) => {
-    this.node = c;
+    for (var i = 0; i < emojis.length; i++) {
+      let emoji = emojis[i];
+      emoji.src = emoji.getAttribute('data-static');
+    }
   }
 
   render () {
@@ -81,7 +66,7 @@ export default class DisplayName extends React.PureComponent {
     }
 
     return (
-      <span className='display-name' ref={this.setRef}>
+      <span className='display-name' onMouseEnter={this.handleMouseEnter} onMouseLeave={this.handleMouseLeave}>
         {displayName} {suffix}
       </span>
     );