src/components/autoMoveDragPlaceHolder.js
function findChild(info, children, handler, reverse) {
  const len = children.length
  if (reverse) {
    for (let i = len - 1; i >= 0; i--) {
      const item = children[i]
      // excluding dragging node
      if (item !== info.node) {
        if (handler(item, i)) {
          return item
        }
      }
    }
  } else {
    for (let i = 0; i < len; i++) {
      const item = children[i]
      // excluding dragging node
      if (item !== info.node) {
        if (handler(item, i)) {
          return item
        }
      }
    }
  }
}
function findChild(info, children, handler, reverse) {
  const len = children.length
  if (reverse) {
    for (let i = len - 1; i >= 0; i--) {
      const item = children[i]
      // excluding dragging node
      if (item !== info.node) {
        if (handler(item, i)) {
          return item
        }
      }
    }
  } else {
    for (let i = 0; i < len; i++) {
      const item = children[i]
      // excluding dragging node
      if (item !== info.node) {
        if (handler(item, i)) {
          return item
        }
      }
    }
  }
}
find child, excluding dragging node default