fix: correct the type errors introduced in #1290

backend/src/routes/payouts.ts

@@ -233,11 +233,12 @@ payoutsRouter.post(
   idempotency(),
   payoutDecisionLimiter,
   asyncHandler(async (req, res) => {
-    const approver = toApprover(requireApprover(req));
+const approver = toApprover(requireApprover(req));
+    const batchId = requireId(req.params.batchId, 'batchId');
     try {
-      const approved = await payoutEngine.approveManualPayout(requireId(req.params.batchId, 'batchId'), approver);
+      const approved = await payoutEngine.approveManualPayout(batchId, approver);
       if (!approved) throw new AppError(409, 'Batch is not awaiting approval', 'INVALID_PAYOUT_STATE');
-      res.json({ data: payoutEngine.getBatch(req.params.batchId) });
+      res.json({ data: payoutEngine.getBatch(batchId) });
     } catch (error) {
       throw asHttpError(error);
     }
@@ -249,11 +250,12 @@ payoutsRouter.post(
   idempotency(),
   payoutDecisionLimiter,
   asyncHandler(async (req, res) => {
-    const approver = toApprover(requireApprover(req));
+const approver = toApprover(requireApprover(req));
+    const batchId = requireId(req.params.batchId, 'batchId');
     try {
-      const rejected = await payoutEngine.rejectManualPayout(requireId(req.params.batchId, 'batchId'), approver);
+      const rejected = await payoutEngine.rejectManualPayout(batchId, approver);
       if (!rejected) throw new AppError(409, 'Batch is not awaiting approval', 'INVALID_PAYOUT_STATE');
-      res.json({ data: payoutEngine.getBatch(req.params.batchId) });
+      res.json({ data: payoutEngine.getBatch(batchId) });
     } catch (error) {
       throw asHttpError(error);
     }
@@ -265,11 +267,12 @@ payoutsRouter.post(
   idempotency(),
   payoutDecisionLimiter,
   asyncHandler(async (req, res) => {
-    const approver = toApprover(requireApprover(req));
+const approver = toApprover(requireApprover(req));
+    const batchId = requireId(req.params.batchId, 'batchId');
     try {
-      const retried = await payoutEngine.retryFailedBatch(requireId(req.params.batchId, 'batchId'), approver);
+      const retried = await payoutEngine.retryFailedBatch(batchId, approver);
       if (!retried) throw new AppError(409, 'Batch is not retryable', 'INVALID_PAYOUT_STATE');
-      res.json({ data: payoutEngine.getBatch(req.params.batchId) });
+      res.json({ data: payoutEngine.getBatch(batchId) });
     } catch (error) {
       throw asHttpError(error);
     }
@@ -281,11 +284,12 @@ payoutsRouter.post(
   idempotency(),
   payoutDecisionLimiter,
   asyncHandler(async (req, res) => {
-    const approver = toApprover(requireApprover(req));
+const approver = toApprover(requireApprover(req));
+    const batchId = requireId(req.params.batchId, 'batchId');
     try {
-      const released = await payoutEngine.releaseReservedFunds(requireId(req.params.batchId, 'batchId'), approver);
+      const released = await payoutEngine.releaseReservedFunds(batchId, approver);
       if (!released) throw new AppError(409, 'Batch has no releasable reservation', 'INVALID_PAYOUT_STATE');
-      res.json({ data: payoutEngine.getBatch(req.params.batchId) });
+      res.json({ data: payoutEngine.getBatch(batchId) });
     } catch (error) {
       throw asHttpError(error);
     }

backend/src/services/fiat-crypto.ts

@@ -57,7 +57,7 @@ export const SUPPORTED_FIAT_PAIRS: Readonly<Record<string, number>> = Object.fre
 export const MAX_FIAT_CONVERSION_AMOUNT = 100_000;
 
 const rateLocks = new Map<string, RateLock>();
-const conversions = Map<string, ConversionRecord>();
+const conversions = new Map<string, ConversionRecord>();
 const refundsInFlight = new Set<string>();
 
 const STELLAR_USDC_ISSUER = 'GBBD47IF6LWK7P7MDEVSCWR7DPUWV3NY3DTQEVFL4NAT4AQH3ZLLFLA5';
@@ -76,11 +76,11 @@ function pairKey(fromCurrency: string, toAsset: string): string {
  * @throws Error `UNSUPPORTED_FIAT_PAIR` when the pair is not quoted.
  */
 function getCurrentRate(fromCurrency: string, toAsset: string): number {
-  const rate = SUPPORTED_FIAT_PAIRS[pairKey(fromCurrency, toAsset)];
-  if (rate === undefined) {
-    throw new Error(`UNSUPPORTED_FIAT_PAIR: ${pairKey(fromCurrency, toAsset)} is not quoted`);
+  const key = pairKey(fromCurrency, toAsset);
+  if (!Object.prototype.hasOwnProperty.call(SUPPORTED_FIAT_PAIRS, key)) {
+    throw new Error(`UNSUPPORTED_FIAT_PAIR: ${key} is not quoted`);
   }
-  return rate;
+  return SUPPORTED_FIAT_PAIRS[key];
 }
 
 function assertNonEmptyId(value: unknown, field: string): string {
@@ -94,6 +94,17 @@ function snapshot(record: ConversionRecord): ConversionRecord {
   return { ...record };
 }
 
+/** Parses a positive settlement amount, collapsing every failure mode onto one sentinel. */
+function parseSettlementAmount(amount: string): bigint {
+  try {
+    const minor = parseDecimalToMinor(amount, CRYPTO_DECIMALS);
+    if (minor > 0n) return minor;
+  } catch {
+    // Any malformed amount falls through to the sentinel below.
+  }
+  throw new Error('INVALID_SETTLEMENT_AMOUNT');
+}
+
 /** Converts a fiat amount into the exact crypto amount at `rate`, without float drift. */
 export function convertFiatToCrypto(fiatAmount: number, rate: number, decimals: number = CRYPTO_DECIMALS): string {
   const fiatMinor = parseDecimalToMinor(fiatAmount, FIAT_DECIMALS);
@@ -171,16 +182,8 @@ export async function confirmConversion(rateLockId: string, userId: string, stri
 
 export async function settleToStellar(destinationAddress: string, amount: string, asset: string): Promise<string> {
   assertNonEmptyId(destinationAddress, 'destination_address');
+  parseSettlementAmount(amount);
 
-  let amountMinor: bigint;
-  try {
-    amountMinor = parseDecimalToMinor(amount, CRYPTO_DECIMALS);
-  } catch {
-    throw new Error('INVALID_SETTLEMENT_AMOUNT');
-  }
-  if (amountMinor <= 0n) {
-    throw new Error('INVALID_SETTLEMENT_AMOUNT');
-  }
   if (!STELLAR_ADDRESS_PATTERN.test(destinationAddress)) {
     throw new Error('INVALID_DESTINATION_ADDRESS');
   }
@@ -245,5 +248,5 @@ export function getRate(fromCurrency: string, toAsset: string): number {
 
 /** True when the pair has a quoted rate. */
 export function isSupportedFiatPair(fromCurrency: string, toAsset: string): boolean {
-  return SUPPORTED_FIAT_PAIRS[pairKey(fromCurrency, toAsset)] !== undefined;
+  return Object.prototype.hasOwnProperty.call(SUPPORTED_FIAT_PAIRS, pairKey(fromCurrency, toAsset));
 }

backend/src/services/payouts/payout-engine.ts

@@ -28,6 +28,9 @@ export const PAYOUT_ASSET_DECIMALS: Readonly<Record<PayoutAsset, number>> = Obje
   EURC: 6,
 });
 
+/** Fallback scale for an asset with no entry above; unused for allowlisted assets. */
+export const DEFAULT_PAYOUT_ASSET_DECIMALS = 6;
+
 /** Engine-level ceiling on a single batch, independent of any approver's limit. */
 export const DEFAULT_PAYOUT_MAX_BATCH_AMOUNT = 1_000_000;
 
@@ -208,7 +211,8 @@ function resolvePositiveLimit(value: number | undefined, fallback: number, code:
 }
 
 function assetDecimals(asset: string): number {
-  return PAYOUT_ASSET_DECIMALS[asset as PayoutAsset] ?? 6;
+  const decimals = (PAYOUT_ASSET_DECIMALS as Record<string, number | undefined>)[asset];
+  return decimals ?? DEFAULT_PAYOUT_ASSET_DECIMALS;
 }
 
 export class PayoutEngine {
@@ -314,7 +318,7 @@ export class PayoutEngine {
 
       for (const schedule of this.schedules) {
         try {
-          const created = this.materialiseBatch(schedule);
+          const created = await this.materialiseBatch(schedule);
           if (!created) continue;
           executedBatches.push(created);
         } catch (error) {