Function setOffsets

code/communication/public/app.js:6491–6528

* In modern non-IE browsers, we can support both forward and backward * selections. * * Note: IE10+ supports the Selection object, but it does not support * the `extend` method, which means that even in modern IE, it's not possible * to programmatically create a backward selection. Thus, for al

(node, offsets)

 * @param {object} offsets
 */
function setOffsets(node, offsets) {
  if (!window.getSelection) {
    return;
  }

  var selection = window.getSelection();
  var length = node[getTextContentAccessor()].length;
  var start = Math.min(offsets.start, length);
  var end = offsets.end === undefined ? start : Math.min(offsets.end, length);

  // IE 11 uses modern selection, but doesn't support the extend method.
  // Flip backward selections, so we can set with a single range.
  if (!selection.extend && start > end) {
    var temp = end;
    end = start;
    start = temp;
  }

  var startMarker = getNodeForCharacterOffset(node, start);
  var endMarker = getNodeForCharacterOffset(node, end);

  if (startMarker && endMarker) {
    if (selection.rangeCount === 1 && selection.anchorNode === startMarker.node && selection.anchorOffset === startMarker.offset && selection.focusNode === endMarker.node && selection.focusOffset === endMarker.offset) {
      return;
    }
    var range = document.createRange();
    range.setStart(startMarker.node, startMarker.offset);
    selection.removeAllRanges();

    if (start > end) {
      selection.addRange(range);
      selection.extend(endMarker.node, endMarker.offset);
    } else {
      range.setEnd(endMarker.node, endMarker.offset);
      selection.addRange(range);
    }
  }
}

function isInDocument(node) {
  return containsNode(document.documentElement, node);