code: function getChildNames(node) {
    if (!node) {
      return [];
    }
  
    const childNames = [];
  
    for (const key of Object.keys(node)) {
      if (key[0] !== '$') {
        childNames.push(key);
      }
    }
  
    return childNames;
  }
docs: All enumerable properties of a node that don't start with `$` are child nodes.