add eslint and prettier

backend/.husky/pre-commit

@@ -0,0 +1 @@
+npx lint-staged

backend/.prettierignore

@@ -0,0 +1,2 @@
+node_modules
+dist

backend/.prettierrc

@@ -0,0 +1,7 @@
+{
+  "semi": true,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 80,
+  "tabWidth": 2
+}

backend/eslint.config.js

@@ -0,0 +1,24 @@
+import js from "@eslint/js";
+import globals from "globals";
+import { defineConfig } from "eslint/config";
+
+export default defineConfig([
+  {
+    files: ["**/*.{js,mjs,cjs}"],
+    plugins: { js },
+    extends: ["js/recommended"],
+    languageOptions: {
+      globals: globals.node
+    },
+    rules: {
+      "no-unused-vars": [
+        "error",
+        {
+          argsIgnorePattern: "^_",
+          varsIgnorePattern: "^_",
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ]
+    }
+  },
+]);

backend/package.json

@@ -7,7 +7,8 @@
   "type": "module",
   "main": "src/index.js",
   "scripts": {
-    "start": "nodemon --watch src/ node src/init.js"
+    "start": "nodemon --watch src/ node src/init.js",
+    "prepare": "husky"
   },
   "dependencies": {
     "cors": "^2.8.5",
@@ -20,6 +21,19 @@
     "swagger-ui-express": "^5.0.1"
   },
   "devDependencies": {
-    "nodemon": "^3.1.10"
+    "@eslint/js": "^9.35.0",
+    "eslint": "^9.35.0",
+    "globals": "^16.4.0",
+    "husky": "^9.1.7",
+    "lint-staged": "^16.1.6",
+    "nodemon": "^3.1.10",
+    "prettier": "^3.6.2"
+  },
+  "lint-staged": {
+    "*.js": [
+      "prettier --write",
+      "eslint --fix",
+      "git add"
+    ]
   }
 }

backend/src/api.js

@@ -234,7 +234,7 @@ router.post("/games", asyncHandler(async (req, res) => {
 
         await conn.commit();
         res.status(201).json({ game: gameRow[0], players });
-    } catch (err) {
+    } catch (_err) {
         await conn.rollback();
         throw new ApiError(500, "Failed to create game");
     } finally {
@@ -299,7 +299,7 @@ router.post("/games/:id/players", asyncHandler(async (req, res) => {
 
         await conn.commit();
         res.status(201).json({ game: gameId, players });
-    } catch (err) {
+    } catch (_err) {
         await conn.rollback();
         throw new ApiError(500, "Failed to add player");
     } finally {
@@ -371,7 +371,7 @@ router.patch("/games/:id/lock", asyncHandler(async (req, res) => {
 
         await conn.commit();
         res.json({ message: "Game locked", turnOrder });
-    } catch (err) {
+    } catch (_err) {
         await conn.rollback();
         throw new ApiError(500, "Failed to lock game");
     } finally {
@@ -483,7 +483,7 @@ router.post("/games/:id/turns", asyncHandler(async (req, res) => {
 
         await conn.commit();
         res.status(201).json({ turnId: result.insertId, nextPlayer });
-    } catch (err) {
+    } catch (_err) {
         await conn.rollback();
         throw new ApiError(500, "Failed to record turn");
     } finally {

backend/src/index.js

@@ -48,13 +48,13 @@ app.use("/api/docs", swaggerUi.serve, swaggerUi.setup(specs));
 app.use("/api", apiRouter);
 
 // has to be last
-app.use((err, _req, res, _next) => {
+app.use((err, _req, res) => {
   if (err instanceof ApiError) {
     return res.status(err.status).json({ status: "error", error: err.message });
   }
 
   console.error(err);
-  res.status(500).json({ status: "error", error: "Internal server error" })
+  res.status(500).json({ status: "error", error: "Internal server error" });
 })
 
 const server = https.createServer({