Place emoji picker top if it is closer to the bottom of the viewport (fixes #7277) (#7314)

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

@@ -162,12 +162,12 @@ class EmojiPickerMenu extends React.PureComponent {
   static defaultProps = {
     style: {},
     loading: true,
-    placement: 'bottom',
     frequentlyUsedEmojis: [],
   };
 
   state = {
     modifierOpen: false,
+    placement: null,
   };
 
   handleDocumentClick = e => {
@@ -298,7 +298,7 @@ export default class EmojiPickerDropdown extends React.PureComponent {
     this.dropdown = c;
   }
 
-  onShowDropdown = () => {
+  onShowDropdown = ({ target }) => {
     this.setState({ active: true });
 
     if (!EmojiPicker) {
@@ -313,6 +313,9 @@ export default class EmojiPickerDropdown extends React.PureComponent {
         this.setState({ loading: false });
       });
     }
+
+    const { top } = target.getBoundingClientRect();
+    this.setState({ placement: top * 2 < innerHeight ? 'bottom' : 'top' });
   }
 
   onHideDropdown = () => {
@@ -324,7 +327,7 @@ export default class EmojiPickerDropdown extends React.PureComponent {
       if (this.state.active) {
         this.onHideDropdown();
       } else {
-        this.onShowDropdown();
+        this.onShowDropdown(e);
       }
     }
   }
@@ -346,7 +349,7 @@ export default class EmojiPickerDropdown extends React.PureComponent {
   render () {
     const { intl, onPickEmoji, onSkinTone, skinTone, frequentlyUsedEmojis } = this.props;
     const title = intl.formatMessage(messages.emoji);
-    const { active, loading } = this.state;
+    const { active, loading, placement } = this.state;
 
     return (
       <div className='emoji-picker-dropdown' onKeyDown={this.handleKeyDown}>
@@ -358,7 +361,7 @@ export default class EmojiPickerDropdown extends React.PureComponent {
           />
         </div>
 
-        <Overlay show={active} placement='bottom' target={this.findTarget}>
+        <Overlay show={active} placement={placement} target={this.findTarget}>
           <EmojiPickerMenu
             custom_emojis={this.props.custom_emojis}
             loading={loading}