add helper function to extract strings

server/src/controllers/controllerUtils.ts

@@ -29,6 +29,14 @@ export const optionalString = (value: unknown, fieldName: string): string | unde
 	throw new AppError({ message: `${fieldName} must be a string`, status: 400 });
 };
 
+export const extractString = (value: unknown): string | undefined => {
+	const candidate = Array.isArray(value) ? value[0] : value;
+	if (typeof candidate !== "string" || candidate.length === 0) {
+		return undefined;
+	}
+	return candidate;
+};
+
 export const optionalNumber = (value: unknown, fieldName: string): number | undefined => {
 	if (value === undefined) {
 		return undefined;

server/src/controllers/incidentController.ts

@@ -1,6 +1,6 @@
 import { AppError } from "@/utils/AppError.js";
 import { Request, Response, NextFunction } from "express";
-import { requireTeamId, requireUserId, requireUserEmail } from "./controllerUtils.js";
+import { requireTeamId, requireUserId, requireUserEmail, extractString } from "./controllerUtils.js";
 import { IIncidentService } from "@/service/index.js";
 import { getIncidentsByTeamQueryValidation, getIncidentSummaryQueryValidation } from "@/validation/incidentValidation.js";
 
@@ -85,12 +85,12 @@ class IncidentController implements IIncidentController {
 			const teamId = requireTeamId(req.user?.teamId);
 			const userId = requireUserId(req.user?.id);
 			const userEmail = requireUserEmail(req.user?.email);
-			const incidentId = req.params?.incidentId;
+			const incidentId = extractString(req.params?.incidentId);
 			if (!incidentId) {
 				throw new AppError({ message: "Incident ID is required", service: SERVICE_NAME, status: 400 });
 			}
 
-			const comment = Array.isArray(req.body.comment) ? req.body.comment[0] : req.body.comment;
+			const comment = extractString(req.body?.comment);
 			const resolvedIncident = await this.incidentService.resolveIncident(incidentId, userId, teamId, comment, userEmail);
 
 			return res.status(200).json({