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Function: makeScanResult()

makeScanResult<Options>(options, getScanIterator): ScanResult<KeyTypeForScanOptions<Options>, ReadonlyJSONValue>

A helper function that makes it easier to implement ReadTransaction.scan with a custom backend.

If you are implementing a custom backend and have an in memory pending async iterable we provide two helper functions to make it easier to merge these together. mergeAsyncIterables and filterAsyncIterable.

For example:

const scanResult = makeScanResult(
  options,
  options.indexName
    ? () => {
        throw Error('not implemented');
      }
    : fromKey => {
        const persisted: AsyncIterable<Entry<ReadonlyJSONValue>> = ...;
        const pending: AsyncIterable<Entry<ReadonlyJSONValue | undefined>> = ...;
        const iter = await mergeAsyncIterables(persisted, pending);
        const filteredIter = await filterAsyncIterable(
          iter,
          entry => entry[1] !== undefined,
        );
        return filteredIter;
      },
);

Type Parameters​

Options​

Options extends ScanOptions

Parameters​

options​

Options

getScanIterator​

Options extends ScanIndexOptions ? GetIndexScanIterator : GetScanIterator

Returns​

ScanResult<KeyTypeForScanOptions<Options>, ReadonlyJSONValue>