🐛 Fix TextArea[autoSize] don't scroll bottom in Firefox (#22014)

close #21870

components/input/ResizableTextArea.tsx

@@ -65,6 +65,7 @@ class ResizableTextArea extends React.Component<TextAreaProps, TextAreaState> {
       raf.cancel(this.resizeFrameId);
       this.resizeFrameId = raf(() => {
         this.setState({ resizing: false });
+        this.fixFirefoxAutoScroll();
       });
     });
   };
@@ -74,6 +75,21 @@ class ResizableTextArea extends React.Component<TextAreaProps, TextAreaState> {
     raf.cancel(this.resizeFrameId);
   }
 
+  // https://github.com/ant-design/ant-design/issues/21870
+  fixFirefoxAutoScroll() {
+    try {
+      if (document.activeElement === this.textArea) {
+        const currentStart = this.textArea.selectionStart;
+        const currentEnd = this.textArea.selectionEnd;
+        this.textArea.setSelectionRange(currentStart, currentEnd);
+      }
+    } catch (e) {
+      // Fix error in Chrome:
+      // Failed to read the 'selectionStart' property from 'HTMLInputElement'
+      // http://stackoverflow.com/q/21177489/3040605
+    }
+  }
+
   renderTextArea = () => {
     const { prefixCls, autoSize, autosize, className, disabled } = this.props;
     const { textareaStyles, resizing } = this.state;