Add update-user endpoint

[kl1874]

What

Adds PUT /users/:id to the users resource: updates an existing user, validates name/email (400 on missing/invalid), and returns 404 for an unknown id instead of crashing. Adds a matching updateUser helper in db/store.js so the route goes through the store like the rest of the resource.

Why

Closes out the users resource with update support, following the same validation/error shape already used by POST /users and the same not-found handling used by GET /users/:id.

What to test

• PUT /users/:id with a valid body updates the user and returns 200 with the updated fields.
• PUT /users/9999 (unknown id) returns 404, not a crash.
• PUT /users/:id with a missing name or email returns 400 with a clear error message.
• npm test is green (9/9), including the pre-existing update-user.test.js suite.

See NOTES.md for the plan, model choice, commit split, and self-review notes.

[mateacademy-ai-mentor]

Review Summary

The updateUser helper in db/store.js is correctly implemented and follows the existing store pattern — it returns undefined for unknown ids, updates the user in place, and is properly exported. However, routes/users.js is not present in the submitted files, which means the PUT /users/:id route handler itself cannot be reviewed. This is a critical blocker: the store helper is only half the deliverable. Without the route file, there is no way to verify that the endpoint exists, that it validates name/email presence with a 400 error, or that it correctly translates the store's undefined return into a 404 response. Please upload routes/users.js so the full implementation can be reviewed against all task requirements.

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[kl1874]

@mateacademy-ai-mentor routes/users.js is present in this PR — it's listed as a modified file in the diff (18 additions, adding the PUT /users/:id handler) alongside db/store.js, CLAUDE.md, and NOTES.md. Confirmed via gh pr view 117 --json files and gh pr diff 117, both of which show the full route diff including the validation (400) and not-found (404) logic. Could you re-check? Re-requesting your review now.

[mateacademy-ai-mentor]

Review Summary

I am requesting changes because the core implementation files needed to verify the task are not available in this review payload, which blocks confirming required functionality. While CLAUDE.md and NOTES.md look good, I cannot inspect routes/users.js and db/store.js here to ensure the PUT /users/:id route validates inputs (400 for missing name/email), returns 404 for unknown ids, and uses the updateUser helper as required. Please upload or paste the full contents (with line numbers) of routes/users.js and db/store.js so I can verify: 1) the route exists and matches the existing error shape from POST /users, 2) it returns 400 when either field is missing, and 3) it returns 404 when updateUser returns undefined. If these files are already committed, re-submit them in this review or include the diffs. Minor: your documentation is clear and aligns with the workflow—no changes needed there. Once I can confirm the route and store behavior, I’ll approve promptly.

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[mateacademy-ai-mentor]

CLAUDE.md correctly documents the workflow and expectations. No action needed here. (No functional code to validate.)

[mateacademy-ai-mentor]

NOTES.md contains a clear plan, model choice, commit split and review summary as required by the checklist. However, the NOTES states the implementation exists; I cannot verify that because the route and store implementation files are not included in this review. Please include routes/users.js and db/store.js (or the diffs) so I can confirm the endpoint validates input, returns 400 on missing fields, and returns 404 for unknown ids as required by the tests.

[mateacademy-ai-mentor]

The previous review summary (from the review context) flagged that routes/users.js was missing from the PR. The user message claims the file is present in the PR. If you believe it is present, please re-upload its contents here (the file text with line markers) so I can inspect it line-by-line and confirm compliance with the checklist.

[kl1874]

@mateacademy-ai-mentor Here are the full contents of both files, with line numbers, as requested.

routes/users.js

 1  const express = require("express");
 2  const store = require("../db/store");
 3
 4  const router = express.Router();
 5
 6  // GET /users — list every user
 7  router.get("/", (req, res) => {
 8    res.json(store.getAllUsers());
 9  });
10
11  // GET /users/:id — fetch a single user, or 404 if it doesn't exist
12  router.get("/:id", (req, res) => {
13    const id = Number(req.params.id);
14    const user = store.getUserById(id);
15
16    if (!user) {
17      return res.status(404).json({ error: "User not found" });
18    }
19
20    res.json(user);
21  });
22
23  // POST /users — create a user; name and email are required
24  router.post("/", (req, res) => {
25    const { name, email } = req.body;
26
27    if (!name || !email) {
28      return res.status(400).json({ error: "name and email are required" });
29    }
30
31    const user = store.createUser({ name, email });
32    res.status(201).json(user);
33  });
34
35  // PUT /users/:id — update an existing user; name and email are required
36  router.put("/:id", (req, res) => {
37    const id = Number(req.params.id);
38    const { name, email } = req.body;
39
40    if (!name || !email) {
41      return res.status(400).json({ error: "name and email are required" });
42    }
43
44    const user = store.updateUser(id, { name, email });
45
46    if (!user) {
47      return res.status(404).json({ error: "User not found" });
48    }
49
50    res.json(user);
51  });
52
53  module.exports = router;

db/store.js

 1  // A tiny in-memory data store. It stands in for a real database so the
 2  // project stays easy to run. Data is not persisted — it resets every time
 3  // the server restarts.
 4
 5  let users = [
 6    { id: 1, name: "Ada Lovelace", email: "ada@example.com" },
 7    { id: 2, name: "Alan Turing", email: "alan@example.com" },
 8  ];
 9
10  let nextId = 3;
11
12  function getAllUsers() {
13    return users;
14  }
15
16  function getUserById(id) {
17    return users.find((user) => user.id === id);
18  }
19
20  function createUser({ name, email }) {
21    const user = { id: nextId, name, email };
22    nextId += 1;
23    users.push(user);
24    return user;
25  }
26
27  function updateUser(id, { name, email }) {
28    const user = getUserById(id);
29
30    if (!user) {
31      return undefined;
32    }
33
34    user.name = name;
35    user.email = email;
36    return user;
37  }
38
39  module.exports = { getAllUsers, getUserById, createUser, updateUser };

Confirming against your three checks:

1. PUT /users/:id exists (line 36) and its 400 error uses the same shape as POST /users ({ error: "name and email are required" }, line 41 vs line 28).
2. Returns 400 when either name or email is missing (line 40-42).
3. Returns 404 when store.updateUser returns undefined for an unknown id (line 46-48), backed by updateUser in db/store.js returning undefined when getUserById finds nothing (line 30-32).

Re-requesting your review now.

[mateacademy-ai-mentor]

Review Summary

Your implementation is approved and complete. The PUT /users/:id endpoint correctly validates name and email, returns 400 with the exact error shape matching POST /users, handles unknown ids with 404 via store.updateUser, and all data access goes through db/store.js as required. Your documentation in CLAUDE.md and NOTES.md is thorough and well-organized. Great work following the existing patterns precisely — this makes the codebase consistent and maintainable. The only minor step before final submission is confirming npm test is green on the pushed branch to fully close the loop.

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