CheezeNotes/static/modules/caret.js

function getStartPositionInLine() {
  let selection = window.getSelection();
  if (selection.rangeCount == 0) {
    return [null, 0];
  }
  let range = selection.getRangeAt(0).cloneRange();
  let obj = range.startContainer;

  let position = range.startOffset;

  if (obj.nodeName == 'DIV' && obj.classList.contains('cheezenotes_line')) {
    return [obj, position];
  }

  let line = null;

  while (obj != null) {
    if (obj.previousSibling != null) {
      obj = obj.previousSibling;
      if (obj.innerText != null) {
        position += obj.innerText.length;
      } else if (obj.length != null) {
        position += obj.length;
      }
    } else if (obj.parentNode != null && obj.parentNode.classList != null && !obj.parentNode.classList.contains('cheezenotes_line')) {
      obj = obj.parentNode;
    } else if (obj.parentNode != null && obj.parentNode.classList != null && obj.parentNode.classList.contains('cheezenotes_line')) {
      line = obj.parentNode;
      obj = null;
    } else {
      obj = null;
    }
  }
  return [line, position];
}

function setStartPositionInLine(line, position) {
  setStartPositionInDiv(line, position)
}

function setStartPositionInDiv(obj, position) {
  let temppos = position;
  if (temppos > obj.innerText.length) {
    return temppos - obj.innerText.length;
  }
  let children = obj.childNodes;
  for (let i = 0; i < children.length; i++) {
    let child = children[i];
    if (child.nodeType == 3) {
      temppos = setStartPositionInText(child, temppos);
    } else {
      temppos = setStartPositionInDiv(child, temppos);
    }
    if (temppos == 0) {
      return temppos;
    }
  }
  return temppos;
}

function setStartPositionInText(obj, position) {
  if (position > obj.length) {
    return position - obj.length;
  }

  let selection = window.getSelection();
  selection.removeAllRanges();
  let range = document.createRange();
  range.setStart(obj, position);
  selection.addRange(range);
  return 0;
}

export { getStartPositionInLine, setStartPositionInLine };