UseTransformer

usage.js

fs.readFileStream("./file.pcapng")
  .useTransform(async function* (source) {
    let block = Buffer.alloc(0);

    for await (const chunk of source) {
      block = Buffer.concat(block, chunk);

      if (block.length < REQUIRED_BLOCK_SIZE_TO_GET_TO_TOTAL_LENGTH) {
        continue;
      }

      const blockExpectedTotalSize = getTotalSizeFromBlock(block);

      if (block.length < blockExpectedTotalSize) {
        continue;
      }

      if (mergedBlock.length >= blockExpectedTotalSize) {
        yield block.slice(0, blockExpectedTotalSize);
        block = block.slice(blockExpectedTotalSize);
      }
    }
  })
  .map((blockBuffer) => parseBufferBasedOnBlockType(blockBuffer))
  .filter((parsedBlock) => parsedblock.dest === "192.168.1.1")
  .toArray();