/**
 * div拖拽
 */
class MoveElement {
  constructor(el) {
    this.$el = el;
    this.init();
  }
  init() {
    const dv = this.$el;

  // 🔴 关键修复：检查 dv 是否为有效 DOM 元素
  if (!dv || typeof dv !== 'object' || !dv.nodeType) {
    console.warn('MoveElement: 传入的 el 不是有效的 DOM 元素', dv);
    return;
  }

  let x = 0;
  let l = 0;
  let isDown = false;

  dv.onmousedown = function(e) {
    x = e.clientX;
    l = dv.offsetLeft;
    isDown = true;
    dv.style.cursor = 'move';
    e.preventDefault();
  };

  dv.onmousemove = function(e) {
    e.preventDefault();
    if (!isDown) return;
    const nx = e.clientX;
    const nl = nx - (x - l);
    dv.style.left = nl + 'px';
  };

  dv.onmouseup = function(e) {
    e.preventDefault();
    isDown = false;
    dv.style.cursor = 'default';
  };
  }
}

export default MoveElement;