Function fetchLightBlock

packages/node/src/utils/substrate.ts:437–477

(
  api: ApiPromise,
  height: number,
)

// TODO why is fetchBlocksBatches a breadth first function rather than depth?
export async function fetchLightBlock(
  api: ApiPromise,
  height: number,
): Promise<IBlock<LightBlockContent>> {
  const blockHash = await api.rpc.chain.getBlockHash(height).catch((e) => {
    logger.error(`failed to fetch BlockHash ${height}`);
    throw ApiPromiseConnection.handleError(e);
  });

  const [header, events, timestamp] = await Promise.all([
    api.rpc.chain.getHeader(blockHash).catch((e) => {
      logger.error(
        `failed to fetch Block Header hash="${blockHash}" height="${height}"`,
      );
      throw ApiPromiseConnection.handleError(e);
    }),
    api.query.system.events.at(blockHash).catch((e) => {
      logger.error(`failed to fetch events at block ${blockHash}`);
      throw ApiPromiseConnection.handleError(e);
    }),
    // TODO: Maybe api.query.timestamp.now.at(blockHash) is the only option. If we do use it we need sufficient tests and errors if a chain doesn't support getting the timestamp.
    (await api.at(blockHash)).query.timestamp.now(),
  ]);

  const blockHeader: BlockHeader = {
    block: { header },
    events: events.toArray(),
  };
  return {
    block: {
      block: blockHeader,
      events: events.map((evt, idx) => merge(evt, { idx, block: blockHeader })),
    },
    getHeader: () => {
      return {
        ...substrateHeaderToHeader(blockHeader.block.header),
        timestamp: new Date(timestamp.toNumber()),
      };
    },
  };
}

export async function fetchBlocksBatchesLight(
  api: ApiPromise,