Function concatBytes

lib/internal/streams/iter/utils.js:128–163

* Concatenate multiple Uint8Arrays into a single Uint8Array. * @param {Uint8Array[]} chunks * @returns {Uint8Array}

(chunks)

 * @returns {Uint8Array}
 */
function concatBytes(chunks) {
  // Empty stream: return zero-length Uint8Array
  if (chunks.length === 0) {
    return new Uint8Array(0);
  }
  // Single chunk: return directly if it covers the entire backing buffer,
  // otherwise return a copy
  if (chunks.length === 1) {
    const chunk = chunks[0];
    // If non-zero offset, skip the remaining buffer checks.
    if (TypedArrayPrototypeGetByteOffset(chunk) === 0) {
      const buf = TypedArrayPrototypeGetBuffer(chunk);
      // SharedArrayBuffer is not available in primordials, so use
      // direct property access for its byteLength.
      const bufByteLength = isSharedArrayBuffer(buf) ?
        buf.byteLength :
        ArrayBufferPrototypeGetByteLength(buf);
      if (TypedArrayPrototypeGetByteLength(chunk) === bufByteLength) {
        return chunk;
      }
    }
    return new Uint8Array(chunk);
  }
  // Multiple chunks: concatenate
  let totalByteLength = 0;
  for (let i = 0; i < chunks.length; i++) {
    totalByteLength += TypedArrayPrototypeGetByteLength(chunks[i]);
  }
  const concatenated = new Uint8Array(totalByteLength);
  let offset = 0;
  for (let i = 0; i < chunks.length; i++) {
    TypedArrayPrototypeSet(concatenated, chunks[i], offset);
    offset += TypedArrayPrototypeGetByteLength(chunks[i]);
  }
  return concatenated;
}

/**
 * Convert an array of chunks (strings or Uint8Arrays) to a Uint8Array[].