周五用裸react写了波一个选择物品弹框拖拽的需求，不是很爽，所以周末用Rx又撸了一个，下面是功能完备的demo：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#dragBox {
position: absolute;
top: 0;
left: 0;
display: flex;
justify-content: center;
align-items: center;
width: 200px;
height: 200px;
background: red;
cursor: move;
}
</style>
</head>
<body>
<div draggable="true" id="dragBox">可被拖拽的Box</div>
<script src="./main.js"></script>
</body>
</html>
import { fromEvent } from 'rxjs';
import { map, tap, switchMap } from 'rxjs/operators';
document.getElementsByTagName('body')[0].addEventListener('dragenter', e => e.preventDefault())
document.getElementsByTagName('body')[0].addEventListener('dragover', e => e.preventDefault())
const $dragBox = document.getElementById('dragBox');
const DRAP_BOX_OFFSET = {
x: $dragBox.clientWidth / 2,
y: $dragBox.clientHeight / 2,
}
const generateDragStream = (type) => {
return fromEvent($dragBox, type);
}
const dragStart$ = generateDragStream('dragstart').pipe(
tap(e => {
e.dataTransfer.setDragImage(document.createElement('div'), 0, 0)
})
)
const dragMove$ = generateDragStream('drag').pipe(
map(e => {
return {
clientX: e.clientX - DRAP_BOX_OFFSET.x,
clientY: e.clientY - DRAP_BOX_OFFSET.y
}
})
)
dragStart$.pipe(
switchMap(() => dragMove$)
).subscribe(v => {
$dragBox.style.top = `${v.clientY}px`;
$dragBox.style.left = `${v.clientX}px`;
});
效果：
拖拽.gif
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