Function parseWalFormat

packages/utils/src/lib/wal.ts:313–344

(
  format: Partial<WalFormat<T>>,
)

 * @returns Parsed WalFormat with defaults filled in
 */
export function parseWalFormat<T extends WalRecord = WalRecord>(
  format: Partial<WalFormat<T>>,
): WalFormat<T> {
  const {
    baseName = 'wal',
    walExtension = '.log',
    finalExtension = walExtension,
    codec = stringCodec<T>(),
  } = format;

  const finalizer =
    format.finalizer ??
    ((records: (T | InvalidEntry<string>)[]) => {
      // Encode each record using the codec before joining.
      // For object types, codec.encode() will JSON-stringify them properly.
      // InvalidEntry records use their raw string value directly.
      const encoded = records.map(record =>
        typeof record === 'object' && record != null && '__invalid' in record
          ? (record as InvalidEntry<string>).raw
          : codec.encode(record as T),
      );
      return `${encoded.join('\n')}\n`;
    });

  return {
    baseName,
    walExtension,
    finalExtension,
    codec,
    finalizer,
  } satisfies WalFormat<T>;
}

/**
 * NOTE: this helper is only used within the scope of wal and sharded wal logic. The rest of the repo avoids sync methods so it is not reusable.