File: public/js/tinymce/src/core/src/main/js/dom/TrimNode.js

define(
  'tinymce.core.dom.TrimNode',

  [
    'ephox.sugar.api.node.Element',
    'tinymce.core.dom.ElementType',
    'tinymce.core.dom.NodeType',
    'tinymce.core.util.Tools'
  ],

  function (Element, ElementType, NodeType, Tools) {
    var surroundedBySpans = function (node) {
      var previousIsSpan = node.previousSibling && node.previousSibling.nodeName === 'SPAN';
      var nextIsSpan = node.nextSibling && node.nextSibling.nodeName === 'SPAN';
      return previousIsSpan && nextIsSpan;
    };

    var isBookmarkNode = function (node) {
      return node && node.tagName === 'SPAN' && node.getAttribute('data-mce-type') === 'bookmark';
    };

    // W3C valid browsers tend to leave empty nodes to the left/right side of the contents - this makes sense
    // but we don't want that in our code since it serves no purpose for the end user
    // For example splitting this html at the bold element:
    //   <p>text 1<span><b>CHOP</b></span>text 2</p>
    // would produce:
    //   <p>text 1<span></span></p><b>CHOP</b><p><span></span>text 2</p>
    // this function will then trim off empty edges and produce:
    //   <p>text 1</p><b>CHOP</b><p>text 2</p>
    var trimNode = function (dom, node) {
      var i, children = node.childNodes;

      if (NodeType.isElement(node) && isBookmarkNode(node)) {
        return;
      }

      for (i = children.length - 1; i >= 0; i--) {
        trimNode(dom, children[i]);
      }

      if (NodeType.isDocument(node) === false) {
        // Keep non whitespace text nodes
        if (NodeType.isText(node) && node.nodeValue.length > 0) {
          // Keep if parent element is a block or if there is some useful content
          var trimmedLength = Tools.trim(node.nodeValue).length;
          if (dom.isBlock(node.parentNode) || trimmedLength > 0) {
            return;
          }
          // Also keep text nodes with only spaces if surrounded by spans.
          // eg. "<p><span>a</span> <span>b</span></p>" should keep space between a and b
          if (trimmedLength === 0 && surroundedBySpans(node)) {
            return;
          }
        } else if (NodeType.isElement(node)) {
          // If the only child is a bookmark then move it up
          children = node.childNodes;

          if (children.length === 1 && isBookmarkNode(children[0])) {
            node.parentNode.insertBefore(children[0], node);
          }

          // Keep non empty elements and void elements
          if (children.length || ElementType.isVoid(Element.fromDom(node))) {
            return;
          }
        }

        dom.remove(node);
      }
      return node;
    };

    return {
      trimNode: trimNode
    };
  }
);