Function index

Sortable.js:392–405

* Returns the index of an element within its parent for a selected set of * elements * @param {HTMLElement} el * @param {selector} selector * @return {number}

(el, selector)

   * @return {number}
   */
  function index(el, selector) {
    var index = 0;
    if (!el || !el.parentNode) {
      return -1;
    }

    /* jshint boss:true */
    while (el = el.previousElementSibling) {
      if (el.nodeName.toUpperCase() !== 'TEMPLATE' && el !== Sortable.clone && (!selector || matches(el, selector))) {
        index++;
      }
    }
    return index;
  }

  /**
   * Returns the scroll offset of the given element, added with all the scroll offsets of parent elements.