Function wrapAndSplit

modules/tinymce/src/core/main/ts/fmt/RemoveFormat.ts:386–447

(
  editor: Editor,
  formatList: Format[],
  formatRoot: Node | undefined,
  container: Node,
  target: Node,
  split: boolean,
  format: Format,
  vars?: FormatVars
)

  );

const wrapAndSplit = (
  editor: Editor,
  formatList: Format[],
  formatRoot: Node | undefined,
  container: Node,
  target: Node,
  split: boolean,
  format: Format,
  vars?: FormatVars
) => {
  let lastClone: Node | undefined;
  let firstClone: Node | undefined;
  const dom = editor.dom;

  // Format root found then clone formats and split it
  if (formatRoot) {
    const formatRootParent = formatRoot.parentNode;

    for (let parent = container.parentNode; parent && parent !== formatRootParent; parent = parent.parentNode) {
      let clone: Node | null = dom.clone(parent, false);

      for (let i = 0; i < formatList.length; i++) {
        clone = removeNodeFormatFromClone(editor, formatList[i], vars, clone);
        if (clone === null) {
          break;
        }
      }

      // Build wrapper node
      if (clone) {
        if (lastClone) {
          clone.appendChild(lastClone);
        }

        if (!firstClone) {
          firstClone = clone;
        }

        lastClone = clone;
      }
    }

    // Never split block elements if the format is mixed
    if (split && (!format.mixed || !dom.isBlock(formatRoot))) {
      container = dom.split(formatRoot, container) ?? container;
    }

    // Wrap container in cloned formats
    if (lastClone && firstClone) {
      target.parentNode?.insertBefore(lastClone, target);
      firstClone.appendChild(target);

      // After splitting the nodes may match with other siblings so we need to attempt to merge them
      // Note: We can't use MergeFormats, as that'd create a circular dependency
      if (FormatUtils.isInlineFormat(format)) {
        mergeSiblings(editor, format, vars, lastClone);
      }
    }