Function computeOrderedLoadCursor

packages/db/src/query/live/utils.ts:432–477

(
  orderByInfo: Pick<
    OrderByOptimizationInfo,
    'orderBy' | 'valueExtractorForRawRow' | 'offset'
  >,
  biggestSentRow: unknown | undefined,
  lastLoadRequestKey: string | undefined,
  alias: string,
  limit: number,
)

 *          otherwise `{ minValues, normalizedOrderBy, loadRequestKey }`.
 */
export function computeOrderedLoadCursor(
  orderByInfo: Pick<
    OrderByOptimizationInfo,
    'orderBy' | 'valueExtractorForRawRow' | 'offset'
  >,
  biggestSentRow: unknown | undefined,
  lastLoadRequestKey: string | undefined,
  alias: string,
  limit: number,
):
  | {
      minValues: Array<unknown> | undefined
      normalizedOrderBy: OrderBy
      loadRequestKey: string
    }
  | undefined {
  const { orderBy, valueExtractorForRawRow, offset } = orderByInfo

  // Extract all orderBy column values from the biggest sent row
  // For single-column: returns single value, for multi-column: returns array
  const extractedValues = biggestSentRow
    ? valueExtractorForRawRow(biggestSentRow as Record<string, unknown>)
    : undefined

  // Normalize to array format for minValues
  let minValues: Array<unknown> | undefined
  if (extractedValues !== undefined) {
    minValues = Array.isArray(extractedValues)
      ? extractedValues
      : [extractedValues]
  }

  // Deduplicate: skip if we already issued an identical load request
  const loadRequestKey = serializeValue({
    minValues: minValues ?? null,
    offset,
    limit,
  })
  if (lastLoadRequestKey === loadRequestKey) {
    return undefined
  }

  const normalizedOrderBy = normalizeOrderByPaths(orderBy, alias)

  return { minValues, normalizedOrderBy, loadRequestKey }
}