Function evaluateWrappedAggregates

packages/db/src/query/compiler/group-by.ts:635–657

* Evaluates wrapped-aggregate expressions against the aggregated row. * Copies synthetic __agg_N values into finalResults so the compiled wrapper * expressions can reference them, evaluates each wrapper, then removes the * synthetic keys so they don't leak onto user-visible result rows.

(
  finalResults: Record<string, any>,
  aggregatedRow: Record<string, any>,
  wrappedAggExprs: Record<string, (data: any) => any>,
  groupKeyCount: number = 0,
)

 * synthetic keys so they don't leak onto user-visible result rows.
 */
function evaluateWrappedAggregates(
  finalResults: Record<string, any>,
  aggregatedRow: Record<string, any>,
  wrappedAggExprs: Record<string, (data: any) => any>,
  groupKeyCount: number = 0,
): void {
  for (const key of Object.keys(aggregatedRow)) {
    if (key.startsWith(`__agg_`)) {
      finalResults[key] = aggregatedRow[key]
    }
  }
  for (let i = 0; i < groupKeyCount; i++) {
    finalResults[`${GROUP_KEY_REF_PREFIX}${i}`] = aggregatedRow[`__key_${i}`]
  }
  for (const [alias, evaluator] of Object.entries(wrappedAggExprs)) {
    finalResults[alias] = evaluator({ $selected: finalResults })
  }
  for (const key of Object.keys(finalResults)) {
    if (key.startsWith(`__agg_`) || key.startsWith(GROUP_KEY_REF_PREFIX)) {
      delete finalResults[key]
    }
  }
}

/**
 * Checks whether an expression contains an aggregate anywhere in its tree.