[WIP] Support animation

examples/animate.less

@@ -0,0 +1,27 @@
+.motion {
+  transition: all .3s;
+}
+
+.item {
+  display: inline-block;
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0 16px;
+  overflow: hidden;
+  line-height: 31px;
+  position: relative;
+
+  &::after {
+    content: '';
+    border-bottom: 1px solid gray;
+    position: absolute;
+    bottom: 0;
+    left: 0;
+    right: 0;
+  }
+
+  button {
+    vertical-align: text-top;
+    margin-right: 8px;
+  }
+}

examples/animate.tsx

@@ -0,0 +1,182 @@
+import * as React from 'react';
+// @ts-ignore
+import CSSMotion from 'rc-animate/lib/CSSMotion';
+import classNames from 'classnames';
+import List, { ScrollInfo } from '../src/List';
+import './animate.less';
+
+let uuid = 0;
+function genItem() {
+  const item = {
+    id: `key_${uuid}`,
+    uuid,
+  };
+  uuid += 1;
+  return item;
+}
+
+const originDataSource: Item[] = [];
+for (let i = 0; i < 100000; i += 1) {
+  originDataSource.push(genItem());
+}
+
+interface Item {
+  id: string;
+  uuid: number;
+}
+
+interface MyItemProps extends Item {
+  visible: boolean;
+  motionAppear: boolean;
+  onClose: (id: string) => void;
+  onLeave: (id: string) => void;
+  onAppear: (...args: any[]) => void;
+  onInsertBefore: (id: string) => void;
+  onInsertAfter: (id: string) => void;
+}
+
+const getCurrentHeight = (node: HTMLElement) => ({ height: node.offsetHeight });
+const getMaxHeight = (node: HTMLElement) => {
+  return { height: node.scrollHeight };
+};
+const getCollapsedHeight = () => ({ height: 0, opacity: 0 });
+
+const MyItem: React.FC<MyItemProps> = (
+  { id, uuid, visible, onClose, onLeave, onAppear, onInsertBefore, onInsertAfter, motionAppear },
+  ref,
+) => {
+  return (
+    <CSSMotion
+      visible={visible}
+      ref={ref}
+      motionName="motion"
+      motionAppear={motionAppear}
+      onAppearStart={getCollapsedHeight}
+      onAppearActive={getMaxHeight}
+      onAppearEnd={onAppear}
+      onLeaveStart={getCurrentHeight}
+      onLeaveActive={getCollapsedHeight}
+      onLeaveEnd={() => {
+        onLeave(id);
+      }}
+    >
+      {({ className, style }, motionRef) => {
+        // if (uuid >= 100) {
+        //   console.log('=>', id, className, style);
+        // }
+        return (
+          <div ref={motionRef} className={classNames('item', className)} style={style} data-id={id}>
+            <div style={{ height: uuid % 2 ? 100 : undefined }}>
+              <button
+                onClick={() => {
+                  onClose(id);
+                }}
+              >
+                Close
+              </button>
+              <button
+                onClick={() => {
+                  onInsertBefore(id);
+                }}
+              >
+                Insert Before
+              </button>
+              <button
+                onClick={() => {
+                  onInsertAfter(id);
+                }}
+              >
+                Insert After
+              </button>
+              {id}
+            </div>
+          </div>
+        );
+      }}
+    </CSSMotion>
+  );
+};
+
+const ForwardMyItem = React.forwardRef(MyItem);
+
+const Demo = () => {
+  const [dataSource, setDataSource] = React.useState(originDataSource);
+  const [closeMap, setCloseMap] = React.useState<{ [id: number]: boolean }>({});
+  const [animating, setAnimating] = React.useState(false);
+  const [insertIndex, setInsertIndex] = React.useState<number>();
+
+  const listRef = React.useRef<List<Item>>();
+
+  const onClose = (id: string) => {
+    setCloseMap({
+      ...closeMap,
+      [id]: true,
+    });
+  };
+
+  const onLeave = (id: string) => {
+    const newDataSource = dataSource.filter(item => item.id !== id);
+    setDataSource(newDataSource);
+  };
+
+  const onAppear = (...args: any[]) => {
+    setAnimating(false);
+  };
+
+  function lockForAnimation() {
+    setAnimating(true);
+  }
+
+  const onInsertBefore = (id: string) => {
+    const index = dataSource.findIndex(item => item.id === id);
+    const newDataSource = [...dataSource.slice(0, index), genItem(), ...dataSource.slice(index)];
+    setInsertIndex(index);
+    setDataSource(newDataSource);
+    lockForAnimation();
+  };
+  const onInsertAfter = (id: string) => {
+    const index = dataSource.findIndex(item => item.id === id) + 1;
+    const newDataSource = [...dataSource.slice(0, index), genItem(), ...dataSource.slice(index)];
+    setInsertIndex(index);
+    setDataSource(newDataSource);
+    lockForAnimation();
+  };
+
+  return (
+    <React.StrictMode>
+      <div>
+        <h2>Animate</h2>
+        <p>Current: {dataSource.length} records</p>
+
+        <List<Item>
+          dataSource={dataSource}
+          data-id="list"
+          height={200}
+          itemHeight={30}
+          itemKey="id"
+          disabled={animating}
+          ref={listRef}
+          style={{
+            border: '1px solid red',
+            boxSizing: 'border-box',
+          }}
+        >
+          {(item, index) => (
+            <ForwardMyItem
+              {...item}
+              motionAppear={animating && insertIndex === index}
+              visible={!closeMap[item.id]}
+              onClose={onClose}
+              onLeave={onLeave}
+              onAppear={onAppear}
+              onInsertBefore={onInsertBefore}
+              onInsertAfter={onInsertAfter}
+            />
+          )}
+        </List>
+      </div>
+    </React.StrictMode>
+  );
+};
+
+export default Demo;

examples/basic.tsx

@@ -25,7 +25,7 @@ const MyItem: React.FC<Item> = ({ id }, ref) => {
 
 const ForwardMyItem = React.forwardRef(MyItem);
 
-class TestItem extends React.Component {
+class TestItem extends React.Component<{ id: number }> {
   render() {
     return <div style={{ lineHeight: '30px' }}>{this.props.id}</div>;
   }
@@ -68,6 +68,7 @@ const Demo = () => {
           dataSource={dataSource}
           height={200}
           itemHeight={30}
+          itemKey="id"
           style={{
             border: '1px solid red',
             boxSizing: 'border-box',

package.json

@@ -39,24 +39,22 @@
     "react-dom": "*"
   },
   "devDependencies": {
-    "@types/lodash": "^4.14.135",
     "@types/react": "^16.8.19",
     "@types/react-dom": "^16.8.4",
     "@types/warning": "^3.0.0",
+    "classnames": "^2.2.6",
     "cross-env": "^5.2.0",
     "enzyme": "^3.1.0",
     "enzyme-adapter-react-16": "^1.0.2",
     "enzyme-to-json": "^3.1.4",
     "father": "^2.13.2",
     "np": "^5.0.3",
+    "rc-animate": "^2.9.1",
     "react": "^v16.9.0-alpha.0",
     "react-dom": "^v16.9.0-alpha.0",
     "typescript": "^3.5.2"
   },
   "dependencies": {
-    "async-validator": "^1.11.2",
-    "lodash": "^4.17.4",
-    "rc-util": "^4.6.0",
-    "warning": "^4.0.3"
+    "rc-util": "^4.8.0"
   }
 }

src/Filler.tsx

@@ -4,30 +4,40 @@ interface FillerProps {
   /** Virtual filler height. Should be `count * itemMinHeight` */
   height: number;
   /** Set offset of visible items. Should be the top of start item position */
-  offset: number;
+  offset?: number;
 
   children: React.ReactNode;
 }
 
 /**
  * Fill component to provided the scroll content real height.
  */
-const Filler: React.FC<FillerProps> = ({ height, offset, children }): React.ReactElement => (
-  <div style={{ height, position: 'relative', overflow: 'hidden' }}>
-    <div
-      style={{
-        marginTop: offset,
-        position: 'absolute',
-        left: 0,
-        right: 0,
-        top: 0,
-        display: 'flex',
-        flexDirection: 'column',
-      }}
-    >
-      {children}
+const Filler: React.FC<FillerProps> = ({ height, offset, children }): React.ReactElement => {
+  let outerStyle: React.CSSProperties = {};
+
+  let innerStyle: React.CSSProperties = {
+    display: 'flex',
+    flexDirection: 'column',
+  };
+
+  if (offset !== undefined) {
+    outerStyle = { height, position: 'relative', overflow: 'hidden' };
+
+    innerStyle = {
+      ...innerStyle,
+      marginTop: offset,
+      position: 'absolute',
+      left: 0,
+      right: 0,
+      top: 0,
+    };
+  }
+
+  return (
+    <div style={outerStyle}>
+      <div style={innerStyle}>{children}</div>
     </div>
-  </div>
-);
+  );
+};
 
 export default Filler;