feat(cascader): support auto scroll to first selected element

src/cascader/Cascader.tsx

@@ -1,6 +1,6 @@
 import React, { useMemo } from 'react';
 import classNames from 'classnames';
-import { pick , omit } from 'lodash-es';
+import { pick, omit } from 'lodash-es';
 import Panel from './components/Panel';
 import SelectInput from '../select-input';
 import FakeArrow from '../common/FakeArrow';
@@ -91,6 +91,30 @@ const Cascader: React.FC<CascaderProps> = (originalProps) => {
   const renderValueDisplay = () => parseContentTNode(props.valueDisplay, valueDisplayParams);
 
   const { setVisible, visible, inputVal, setInputVal } = cascaderContext;
+
+  const updateScrollTop = (content: HTMLDivElement) => {
+    const cascaderMenuList = content.querySelectorAll(`.${COMPONENT_NAME}__menu`);
+    requestAnimationFrame(() => {
+      cascaderMenuList.forEach((menu: HTMLDivElement) => {
+        const firstSelectedNode: HTMLDivElement =
+          menu?.querySelector(`.${classPrefix}-is-selected`) || menu?.querySelector(`.${classPrefix}-is-expanded`);
+        if (!firstSelectedNode || !menu) return;
+
+        const { paddingBottom } = getComputedStyle(firstSelectedNode);
+        const { marginBottom } = getComputedStyle(menu);
+        const elementBottomHeight = parseInt(paddingBottom, 10) + parseInt(marginBottom, 10);
+
+        const updateValue =
+          firstSelectedNode.offsetTop -
+          menu.offsetTop -
+          (menu.clientHeight - firstSelectedNode.clientHeight) +
+          elementBottomHeight;
+        // eslint-disable-next-line no-param-reassign
+        menu.scrollTop = updateValue;
+      });
+    });
+  };
+
   return (
     <SelectInput
       className={classNames(COMPONENT_NAME, props.className)}
@@ -114,6 +138,7 @@ const Cascader: React.FC<CascaderProps> = (originalProps) => {
       valueDisplay={renderValueDisplay()}
       suffix={props.suffix}
       suffixIcon={renderSuffixIcon()}
+      updateScrollTop={updateScrollTop}
       popupProps={{
         ...props.popupProps,
         overlayInnerStyle: panels.length && !props.loading ? { width: 'auto' } : {},

src/cascader/_example/multiple.tsx

@@ -3,7 +3,7 @@ import { Cascader } from 'tdesign-react';
 import type { CascaderProps, CascaderValue } from 'tdesign-react';
 
 export default function Example() {
-  const [value, setValue] = useState<CascaderValue>(['1.1']);
+  const [value, setValue] = useState<CascaderValue>(['8.1']);
   const options = [
     {
       label: '选项一',
@@ -37,6 +37,90 @@ export default function Example() {
         },
       ],
     },
+    {
+      label: '选项三',
+      value: '3',
+      children: [
+        {
+          label: '子选项一',
+          value: '3.1',
+        },
+        {
+          label: '子选项二',
+          value: '3.2',
+        },
+      ],
+    },
+    {
+      label: '选项四',
+      value: '4',
+      children: [
+        {
+          label: '子选项一',
+          value: '4.1',
+        },
+        {
+          label: '子选项二',
+          value: '4.2',
+        },
+      ],
+    },
+    {
+      label: '选项五',
+      value: '5',
+      children: [
+        {
+          label: '子选项一',
+          value: '5.1',
+        },
+        {
+          label: '子选项二',
+          value: '5.2',
+        },
+      ],
+    },
+    {
+      label: '选项六',
+      value: '6',
+      children: [
+        {
+          label: '子选项一',
+          value: '6.1',
+        },
+        {
+          label: '子选项二',
+          value: '6.2',
+        },
+      ],
+    },
+    {
+      label: '选项七',
+      value: '7',
+      children: [
+        {
+          label: '子选项一',
+          value: '7.1',
+        },
+        {
+          label: '子选项二',
+          value: '7.2',
+        },
+      ],
+    },
+    {
+      label: '选项8',
+      value: '8',
+      children: [
+        {
+          label: '子选项一',
+          value: '8.1',
+        },
+        {
+          label: '子选项二',
+          value: '8.2',
+        },
+      ],
+    },
   ];
 
   const onChange: CascaderProps['onChange'] = (value) => {

test/snap/__snapshots__/csr.test.jsx.snap

@@ -19620,9 +19620,9 @@ exports[`csr snapshot test > csr test src/cascader/_example/multiple.tsx 1`] = `
               class="t-tag t-tag--default t-tag--dark"
             >
               <span
-                title="选项一/子选项一"
+                title="选项8/子选项一"
               >
-                选项一/子选项一
+                选项8/子选项一
               </span>
               <svg
                 class="t-icon t-icon-close t-tag__icon-close"