Function fetchBlocksBatches

packages/node/src/utils/substrate.ts:396–434

(
  api: ApiPromise,
  blockArray: number[],
  overallSpecVer?: number,
)

}

export async function fetchBlocksBatches(
  api: ApiPromise,
  blockArray: number[],
  overallSpecVer?: number,
): Promise<IBlock<BlockContent>[]> {
  const blocks = await fetchBlocksArray(api, blockArray);
  const blockHashs = blocks.map((b) => b.block.header.hash);
  const parentBlockHashs = blocks.map((b) => b.block.header.parentHash);
  // If overallSpecVersion passed, we don't need to use api to get runtimeVersions
  // wrap block with specVersion
  // If specVersion changed, we also not guarantee in this batch contains multiple runtimes,
  // therefore we better to fetch runtime over all blocks
  const [blockEvents, runtimeVersions] = await Promise.all([
    fetchEventsRange(api, blockHashs),
    overallSpecVer !== undefined // note, we need to be careful if spec version is 0
      ? undefined
      : fetchRuntimeVersionRange(api, parentBlockHashs),
  ]);

  return blocks.map((block, idx) => {
    const events = blockEvents[idx];
    const parentSpecVersion =
      overallSpecVer ?? runtimeVersions?.[idx].specVersion.toNumber();
    assert(parentSpecVersion !== undefined, 'parentSpecVersion is undefined');

    const wrappedBlock = wrapBlock(block, events.toArray(), parentSpecVersion);
    const wrappedExtrinsics = wrapExtrinsics(wrappedBlock, events);
    const wrappedEvents = wrapEvents(wrappedExtrinsics, events, wrappedBlock);

    return {
      getHeader: () => substrateBlockToHeader(wrappedBlock),
      block: {
        block: wrappedBlock,
        extrinsics: wrappedExtrinsics,
        events: wrappedEvents,
      },
    };
  });
}

// TODO why is fetchBlocksBatches a breadth first function rather than depth?
export async function fetchLightBlock(