bfs.ts

/**
 * Creates as an iterable queue for use in a breadth-first search.
 *
 * If you iterate over this queue, you will get a breadth-first search for
 * free.
 *
 * @param rootNode - First node to add to the queue.
 * @yields The next AST node in the queue.
 * @returns The complete queue of nodes that were added.
 *
 */
export function* createNodeQueue(root: ASTNode): IterableIterator<ASTNode> {
  const queue: ASTNode[] = [root];

  for (const node of queue) {
    queue.push(...getChildNodes(node));
    yield node;
  }

  return queue;
}

/**
 * Gets all of the child nodes if there are any.
 *
 * Gracefully falls back to an empty array if you provide a node that doesn't
 * support child nodes (e.g. a text node or comment node).
 *
 * @param node An AST Node
 * @returns An array of AST Nodes that are the children of the provided node.
 */
export const getChildNodes = (node: ASTNode): ASTNode[] => node.childNodes || [];