Settings patch creates arbitrary keys

Code reviewSecuritySenior–Staff~24 min

Review this Node settings updater that applies a client-supplied dot-path patch.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 24 min

Mark a line and say what kind of problem it is.0 findings

1function applyPatch(target, patch) {

2 for (const { path, value } of patch) {

3 const keys = path.split('.');

4 let obj = target;

5 for (let i = 0; i < keys.length - 1; i++) {

6 const k = keys[i];

7 if (!(k in obj)) obj[k] = {};

8 obj = obj[k];

9 }

10 obj[keys[keys.length - 1]] = value;

11 }

12 return target;

13}

15app.patch('/settings', (req, res) => {

16 applyPatch(currentSettings, req.body.ops);

17 res.json(currentSettings);

18});

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.