Function decompress

src/cmap/wire_protocol/compression.ts:110–144

(
  compressorID: number,
  compressedData: Uint8Array
)

// Decompress a message using the given compressor
export async function decompress(
  compressorID: number,
  compressedData: Uint8Array
): Promise<Uint8Array> {
  if (
    compressorID !== Compressor.snappy &&
    compressorID !== Compressor.zstd &&
    compressorID !== Compressor.zlib &&
    compressorID !== Compressor.none
  ) {
    throw new MongoDecompressionError(
      `Server sent message compressed using an unsupported compressor. (Received compressor ID ${compressorID})`
    );
  }

  switch (compressorID) {
    case Compressor.snappy: {
      Snappy ??= loadSnappy();
      return await Snappy.uncompress(compressedData, { asBuffer: true });
    }
    case Compressor.zstd: {
      loadZstd();
      if ('kModuleError' in zstd) {
        throw zstd['kModuleError'];
      }
      return await zstd.decompress(compressedData);
    }
    case Compressor.zlib: {
      return await zlibInflate(compressedData);
    }
    default: {
      return compressedData;
    }
  }
}

/**
 * Load ZStandard if it is not already set.