Function normalizeDOMPoint

packages/editor/src/utils/dom.ts:18–43

(domPoint: DOMPoint)

 */

export const normalizeDOMPoint = (domPoint: DOMPoint): DOMPoint => {
  let [node, offset] = domPoint

  // If it's an element node, its offset refers to the index of its children
  // including comment nodes, so try to find the right text child node.
  if (isDOMElement(node) && node.childNodes.length) {
    let isLast = offset === node.childNodes.length
    let index = isLast ? offset - 1 : offset
    ;[node, index] = getEditableChildAndIndex(node, index, isLast ? 'backward' : 'forward')
    // If the editable child found is in front of input offset, we instead seek to its end
    isLast = index < offset

    // If the node has children, traverse until we have a leaf node. Leaf nodes
    // can be either text nodes, or other void DOM nodes.
    while (isDOMElement(node) && node.childNodes.length) {
      const i = isLast ? node.childNodes.length - 1 : 0
      node = getEditableChild(node, i, isLast ? 'backward' : 'forward')
    }

    // Determine the new offset inside the text node.
    offset = isLast && node.textContent != null ? node.textContent.length : 0
  }

  // Return the node and offset.
  return [node, offset]
}

/**
 * Determines wether the active element is nested within a shadowRoot