flattenNodes.js

// Flatten an array of nodes, returning all nodes
// of the tree without their children.
const flattenNodeTree = (node) => {
  const { children, ...otherProps } = node;

  if (!children) {
    return [{ ...otherProps }];
  }

  return [{ ...otherProps }, ...[].concat(...children.map(flattenNodeTree))];
};