Fix first poll option not being focused when adding a poll (#13740)

Fixes #13698

app/javascript/mastodon/features/compose/components/poll_form.js

@@ -27,6 +27,7 @@ class Option extends React.PureComponent {
     title: PropTypes.string.isRequired,
     index: PropTypes.number.isRequired,
     isPollMultiple: PropTypes.bool,
+    autoFocus: PropTypes.bool,
     onChange: PropTypes.func.isRequired,
     onRemove: PropTypes.func.isRequired,
     onToggleMultiple: PropTypes.func.isRequired,
@@ -71,7 +72,7 @@ class Option extends React.PureComponent {
   }
 
   render () {
-    const { isPollMultiple, title, index, intl } = this.props;
+    const { isPollMultiple, title, index, autoFocus, intl } = this.props;
 
     return (
       <li>
@@ -96,6 +97,7 @@ class Option extends React.PureComponent {
             onSuggestionsClearRequested={this.onSuggestionsClearRequested}
             onSuggestionSelected={this.onSuggestionSelected}
             searchTokens={[':']}
+            autoFocus={autoFocus}
           />
         </label>
 
@@ -146,10 +148,12 @@ class PollForm extends ImmutablePureComponent {
       return null;
     }
 
+    const autoFocusIndex = options.indexOf('');
+
     return (
       <div className='compose-form__poll-wrapper'>
         <ul>
-          {options.map((title, i) => <Option title={title} key={i} index={i} onChange={onChangeOption} onRemove={onRemoveOption} isPollMultiple={isMultiple} onToggleMultiple={this.handleToggleMultiple} {...other} />)}
+          {options.map((title, i) => <Option title={title} key={i} index={i} onChange={onChangeOption} onRemove={onRemoveOption} isPollMultiple={isMultiple} onToggleMultiple={this.handleToggleMultiple} autoFocus={i === autoFocusIndex} {...other} />)}
         </ul>
 
         <div className='poll__footer'>