function adjustInsertPositionForStructuredNode()

in packages/roosterjs-editor-dom/lib/edit/adjustInsertPosition.ts [101:171]
62 lines of code
26 McCabe index (conditional complexity)

function adjustInsertPositionForStructuredNode(
    root: HTMLElement,
    nodeToInsert: Node,
    position: NodePosition,
    range: Range
): NodePosition {
    let rootNodeToInsert = nodeToInsert;

    if (rootNodeToInsert.nodeType == NodeType.DocumentFragment) {
        let rootNodes = toArray(rootNodeToInsert.childNodes).filter(
            (n: ChildNode) => getTagOfNode(n) != 'BR'
        );
        rootNodeToInsert = rootNodes.length == 1 ? rootNodes[0] : null;
    }

    let tag = getTagOfNode(rootNodeToInsert);
    let hasBrNextToRoot = tag && getTagOfNode(rootNodeToInsert.nextSibling) == 'BR';
    let listItem = findClosestElementAncestor(position.node, root, 'LI');
    let listNode = listItem && findClosestElementAncestor(listItem, root, 'OL,UL');
    let tdNode = findClosestElementAncestor(position.node, root, 'TD,TH');
    let trNode = tdNode && findClosestElementAncestor(tdNode, root, 'TR');

    if (tag == 'LI') {
        tag = listNode ? getTagOfNode(listNode) : 'UL';
        rootNodeToInsert = wrap(rootNodeToInsert, tag);
    }

    if ((tag == 'OL' || tag == 'UL') && getTagOfNode(rootNodeToInsert.firstChild) == 'LI') {
        let shouldInsertListAsText = !rootNodeToInsert.firstChild.nextSibling && !hasBrNextToRoot;

        if (hasBrNextToRoot && rootNodeToInsert.parentNode) {
            safeRemove(rootNodeToInsert.nextSibling);
        }

        if (shouldInsertListAsText) {
            unwrap(rootNodeToInsert.firstChild);
            unwrap(rootNodeToInsert);
        } else if (getTagOfNode(listNode) == tag) {
            unwrap(rootNodeToInsert);
            position = new Position(
                listItem,
                isPositionAtBeginningOf(position, listItem)
                    ? PositionType.Before
                    : PositionType.After
            );
        }
    } else if (tag == 'TABLE' && trNode) {
        // When inserting a table into a table, if these tables have the same column count, and
        // current position is at beginning of a row, then merge these two tables
        let newTable = new VTable(<HTMLTableElement>rootNodeToInsert);
        let currentTable = new VTable(<HTMLTableCellElement>tdNode);
        if (
            currentTable.col == 0 &&
            tdNode == currentTable.getCell(currentTable.row, 0).td &&
            newTable.cells[0] &&
            newTable.cells[0].length == currentTable.cells[0].length &&
            isPositionAtBeginningOf(position, tdNode)
        ) {
            if (
                getTagOfNode(rootNodeToInsert.firstChild) == 'TBODY' &&
                !rootNodeToInsert.firstChild.nextSibling
            ) {
                unwrap(rootNodeToInsert.firstChild);
            }
            unwrap(rootNodeToInsert);
            position = new Position(trNode, PositionType.After);
        }
    }

    return position;
}