Function getCompressionFormatFromHeader

src/utils/compression.ts:106–118

(
  header: Buffer,
)

}

export const getCompressionFormatFromHeader = (
  header: Buffer,
): CompressionFormat | undefined => {
  if (header.length >= GZIP_MAGIC.length && header.subarray(0, GZIP_MAGIC.length).equals(GZIP_MAGIC)) {
    return CompressionFormat.GZIP
  }

  if (header.length >= XZ_MAGIC.length && header.subarray(0, XZ_MAGIC.length).equals(XZ_MAGIC)) {
    return CompressionFormat.XZ
  }

  return undefined
}

const readFileHeader = async (filePath: string, bytes = XZ_MAGIC.length): Promise<Buffer> => {
  const fileHandle = await open(filePath, 'r')