using npmjs.com/archiver package to create zip archive with given structure

examples_npm_archiver.ts

interface FileEntry {
  path: string
  buffer?: Buffer
  contents?: FileEntry[]
}

async function zipFiles (files: FileEntry[]): Promise<Buffer> {
  const archive = archiver('zip', { zlib: { level: 9 } })
  const output: Buffer[] = []

  archive.on('data', (data: Buffer) => output.push(data))
  archive.on('error', (err: any) => { throw err })

  const addFilesToArchive = (entries: FileEntry[], rootPath = '') => {
    for (const entry of entries) {
      const fullPath = path.join(rootPath, entry.path)
      if (entry.contents) {
        addFilesToArchive(entry.contents, fullPath)
      } else if (entry.buffer) {
        archive.append(entry.buffer, { name: fullPath })
      }
    }
  }

  addFilesToArchive(files)

  await archive.finalize()

  return Buffer.concat(output)
}