Language focus

AI code review for JavaScript

JavaScript spans browsers, Node services, and bundled front ends. CodeCritic reviews real diffs and pasted snippets with enough surrounding context to catch async mistakes, module boundary bugs, and security seams that linters treat as style.

Node & browsersFramework-awareESM & CJSPaste or GitHub PRFree tier
GitHub code review

Online paste review · All languages

Review focus

What we look for in JavaScript changes

Generic “looks fine” feedback is useless in JS. The model is steered toward failure modes that survive green CI: wrong async ordering, silent behavior changes after refactors, and XSS-shaped APIs.

  • Async/await and Promise chains: forgotten error handlers, floating promises in request handlers, and race windows between await points.
  • Module graphs: default export reshuffles, circular requires, and ESM/CJS interop that breaks only in production bundles.
  • React/Vue/Angular edges: stale closures in hooks, missing keys, effect dependency mistakes, and server/client boundary leaks in SSR apps.
  • Security: dangerouslySetInnerHTML, open redirects, JWT storage in localStorage, weak CSP, and prototype pollution via object spread.
  • Refactors that preserve types or lint rules but change runtime behavior (optional chaining on nullish vs falsy, loose equality drift).
  • Test gaps: happy-path unit tests that never exercise the branch the diff actually changes.

AI review does not replace threat modeling or PCI/HIPAA sign-off. Use it as a fast second pass; owners who know deployment risk still approve merge.

Stacks

Common JavaScript codebases we see

Node & Express-style APIs

Middleware ordering, body-parser limits, auth bypass via alternate routes, and logging that prints tokens.

Browser & SPA bundles

Client-side secret leakage, oversized bundles with dead code paths, and fetch wrappers that drop credentials mode.

Tooling chains

Babel/SWC transforms that hide the runtime code reviewers read; source maps are not a substitute for reviewing emitted behavior.

Workflow

Run a JavaScript review in minutes

Start in the browser to validate signal quality, then wire GitHub when the team is ready for PR-level automation.
  1. 1

    Paste or connect a repo

    Sign up, open a new review, and paste a module or upload a file. For ongoing work, connect GitHub and target the PR that contains your JS changes.

  2. 2

    Let detection set context

    CodeCritic detects language and framework cues from the snippet or diff so findings reference the stack you actually use, not generic advice.

  3. 3

    Triage by severity

    Issues arrive grouped with short explanations. Fix blocking items first, then decide which suggestions are worth debate in human review.

  4. 4

    Scale to PR comments

    When ready, enable GitHub integration so the same engine comments on pull requests your team already merges through.

How to use it

JavaScript review without drowning in noise

Paste flows work best with a coherent unit: a route handler plus its helpers, a React component with hooks it calls, or a service module - not three unrelated exports stripped of imports.

Linters and formatters should stay in CI. CodeCritic is aimed at reasoning: “this change can throw before the catch runs” beats “prefer const”.

For large refactors, split behavior changes from mechanical moves. Mixed diffs confuse every reviewer, automated or human.

If you ship through GitHub, connect the repository once and run reviews on the PR diff so comments sit next to the lines reviewers already discuss.

Paid tiers add API and Action automation when you want the same checks on every push, not only when someone remembers to paste.

Pair automated output with your existing test suite: AI can miss business rules that only your domain tests encode.

Details: Integrations, Limitations, Pricing.

Before you merge JavaScript

  • Context size: Include enough surrounding code that imports, exports, and middleware order are visible to the model.
  • Async paths: Re-read every new await in request handlers and background jobs for failure propagation.
  • User input: Trace untrusted data through parsers, template renderers, and JSON.stringify used in HTML.
  • Human owner: Assign a reviewer who can explain the product behavior the diff touches, not only syntax.

FAQ

JavaScript code review FAQ

Yes. Reviews run on JavaScript source regardless of runtime target. Include hints in the snippet (framework imports, process.env usage) so feedback stays relevant.

Try AI code review on your JavaScript

Start free in the browser, then connect GitHub when the team wants reviews on every pull request.

How it works