Function flattenTree

frontend/packages/common/src/utils/postcat.tsx:27–55

(
  tree: T[] = [],
  childrenKey: keyof T = 'children',
  pathKey: keyof T = 'id'
)

 * each enhanced with a path property representing its location within the tree.
 */
export function flattenTree<T extends TreeNode<T>>(
  tree: T[] = [],
  childrenKey: keyof T = 'children',
  pathKey: keyof T = 'id'
): T[] {
  const result: T[] = []
  let __globalIndex__ = 0

  const flatten = (node: T, path: string[], __levelIndex__: number, parent: T | null = null): void => {
    const { [childrenKey]: children, ...restNode } = node
    const nodeWithPath: T = {
      ...restNode,
      __raw__: node,
      path: [...path, node[pathKey]] as string[],
      __globalIndex__,
      __levelIndex__
    } as T
    nodeWithPath[childrenKey] = children
    nodeWithPath.parent = parent ?? null
    result.push(nodeWithPath)
    __globalIndex__++

    const list: T[] = (children || []) as unknown as T[]
    list.forEach((child: T, childIndex: number) => flatten(child, nodeWithPath.path || [], childIndex, node))
  }

  tree.forEach((node, index) => flatten(node, [], index))
  return result
}

export function byteToString(inputByteLength: number): string {
  inputByteLength = inputByteLength || 0