Merge pull request #1 from rolex17/add-update-user-endpoint

Add PUT endpoint to update existing users

Author: rolex17

NOTES.md

@@ -0,0 +1,26 @@
+# Ship a Change - Implementation Notes
+
+## Plan
+The plan was to add a PUT endpoint for updating users. The implementation required two changes:
+1. Add an `updateUser` function to `db/store.js` that finds a user by ID and updates their name and email
+2. Add a PUT route to `routes/users.js` that validates input (both name and email required), handles the not-found case (404), and returns the updated user (200)
+
+I did not need to edit the plan — it was clear and complete.
+
+## Model Choice
+I used Claude Haiku (haiku-4.5-20251001) because this is a small, straightforward feature with clear requirements from the tests. The task involves following an existing pattern (similar to POST endpoint) and the logic is simple enough that a faster model is efficient here.
+
+## Commit Split
+I made one commit containing both file changes:
+- `db/store.js`: Added the `updateUser` function
+- `routes/users.js`: Added the PUT endpoint with validation
+
+This is one logical change (adding the update user feature) and fits together naturally — the route needs the store function, so splitting them would create a temporarily broken state.
+
+## Review Findings
+The implementation correctly handles all three test cases:
+- ✅ Updates an existing user and returns 200 with the updated data
+- ✅ Returns 404 when the user doesn't exist
+- ✅ Returns 400 when required fields are missing
+
+The validation logic mirrors the POST endpoint, ensuring consistency. No issues found.

db/store.js

@@ -24,4 +24,14 @@ function createUser({ name, email }) {
   return user;
 }
 
-module.exports = { getAllUsers, getUserById, createUser };
+function updateUser(id, { name, email }) {
+  const user = users.find((u) => u.id === id);
+  if (!user) {
+    return null;
+  }
+  user.name = name;
+  user.email = email;
+  return user;
+}
+
+module.exports = { getAllUsers, getUserById, createUser, updateUser };

routes/users.js

@@ -32,4 +32,22 @@ router.post("/", (req, res) => {
   res.status(201).json(user);
 });
 
+// PUT /users/:id — update a user; name and email are required
+router.put("/:id", (req, res) => {
+  const { name, email } = req.body;
+
+  if (!name || !email) {
+    return res.status(400).json({ error: "name and email are required" });
+  }
+
+  const id = Number(req.params.id);
+  const user = store.updateUser(id, { name, email });
+
+  if (!user) {
+    return res.status(404).json({ error: "User not found" });
+  }
+
+  res.json(user);
+});
+
 module.exports = router;