@alifd/overlay/demo/popup.md

overlay base component

---
title: Popup弹层
order: 2
---

`Popup` 是对 `Overlay` 的封装，它接收某个节点作为触发节点，弹出一个浮层，这个浮层默认情况下使用这个节点作为定位的参照对象。

```jsx
import Overlay from '@alifd/overlay';

const { Popup } = Overlay;

const style = {
  width: 400,
  height: 100,
  padding: 10,
  background: '#fff',
  borderRadius: 2,
  boxShadow: '2px 2px 20px rgba(0, 0, 0, 0.15)',
};

const FunctionalOverlay = (props) => (
  <span {...props} style={style}>
    Hello World From Popup!
  </span>
);

const FunctionalButton = (props) => (
  <button style={{ border: '4px solid' }} {...props}>
    Open
  </button>
);

ReactDOM.render(
  <div>
    <Popup overlay={<FunctionalOverlay />} triggerType="click">
      <FunctionalButton />
    </Popup>
    <br />
    <br />
    <Popup overlay={<FunctionalOverlay />} triggerType="click" triggerClickKeyCode={40}>
      <input placeholder="Use Down Arrow to open" />
    </Popup>
  </div>,
  mountNode
);
```