Question

export function foreachTree(data, childrenName = 'children', callback) {
  for (let i = 0; i < data.length; i++) {
    callback(data[i]);
    if (data[i][childrenName] && data[i][childrenName].length > 0) {
      foreachTree(data[i][childrenName], childrenName, callback);
    }
  }
}