Improve ESLint rules for JSX (#3608)

* Add react/no-string-refs ESLint rule

* Add react/jsx-boolean-value ESLint rule

* Add react/jsx-closing-bracket-location ESLint rule

* Add react/jsx-indent ESLint rule

* Add react/jsx-curly-spacing ESLint rule

* Add react/jsx-equals-spacing ESLint rule

* Add react/jsx-first-prop-new-line ESLint rule

* Add react/jsx-no-duplicate-props ESLint rule

* Add react/jsx-tag-spacing ESLint rule

1 files changed, 3 insertions, 3 deletions

diff --git a/app/javascript/mastodon/components/dropdown_menu.js b/app/javascript/mastodon/components/dropdown_menu.js
index e637c5f79..5712cffab 100644
--- a/app/javascript/mastodon/components/dropdown_menu.js
+++ b/app/javascript/mastodon/components/dropdown_menu.js
@@ -53,13 +53,13 @@ class DropdownMenu extends React.PureComponent {
 
   renderItem = (item, i) => {
     if (item === null) {
-      return <li key={ 'sep' + i } className='dropdown__sep' />;
+      return <li key={`sep-${i}`} className='dropdown__sep' />;
     }
 
     const { text, action, href = '#' } = item;
 
     return (
-      <li className='dropdown__content-list-item' key={ text + i }>
+      <li className='dropdown__content-list-item' key={`${text}-${i}`}>
         <a href={href} target='_blank' rel='noopener' onClick={this.handleClick} data-index={i} className='dropdown__content-list-link'>
           {text}
         </a>
@@ -81,7 +81,7 @@ class DropdownMenu extends React.PureComponent {
     return (
       <Dropdown ref={this.setRef} onShow={this.handleShow} onHide={this.handleHide}>
         <DropdownTrigger className='icon-button' style={{ fontSize: `${size}px`, width: `${size}px`, lineHeight: `${size}px` }} aria-label={ariaLabel}>
-          <i className={ `fa fa-fw fa-${icon} dropdown__icon` }  aria-hidden={true} />
+          <i className={`fa fa-fw fa-${icon} dropdown__icon`}  aria-hidden />
         </DropdownTrigger>
 
         <DropdownContent className={directionClass}>