The Biggest Mistakes Frontend Developers Make in Code Reviews

Code reviews can be a game changer for frontend teams when done right. They help catch bugs before they reach production, improve code quality, and spread knowledge across the team. But too often, reviews turn into a frustrating nitpick session.

If you've ever been part of a code review that felt like a waste of time (or worse, an unnecessary headache), you're not alone. Here are some of the biggest mistakes frontend developers make during code reviews and how to fix them.

1. Focusing on Style Instead of Substance

We’ve all seen it happen - a review thread turns into a debate about tabs vs. spaces, or whether a function should be named fetchData or getData

How to fix it:

• Automate style enforcement. Use tools like ESLint and Prettier so reviewers don’t have to comment on formatting.
• Prioritize what matters. Focus on functionality, performance, security, and maintainability. Style should only be an issue if it affects readability or introduces inconsistencies.

2. Not Testing the Code Locally

It’s tempting to skim through the code and approve it if everything looks okay. But code that looks fine in a GitHub diff can behave unexpectedly when you actually run it.

How to fix it:

• Pull the branch and test the changes yourself. Click around, try edge cases, and make sure the feature works as expected.
• Use browser dev tools. Check for performance issues, console errors, and accessibility problems.
• Run the tests. If tests are included, make sure they actually pass.

3.Ignoring Performance Implications

Frontend performance matters a lot. A piece of code might work but still introduce subtle performance issues like unnecessary re-renders, large bundle sizes, or excessive API calls.

How to fix it:

• Look out for inefficient state updates. Is this new component causing unnecessary re-renders? Should it be memoized?
• Check for bloated dependencies. Did the PR introduce a heavy library for something that could have been done natively?
• Test for responsiveness. Does the new code affect load times, animations, or interactions?

4. Skipping Accessibility Checks

Accessibility (a11y) is often treated as an afterthought until a user with a disability struggles with your app. Basic mistakes like missing alt text, poor contrast, or broken keyboard navigation can make an app unusable for many people.

How to fix it:

• Test with a screen reader. Can you navigate and understand the content without a mouse?
• Use accessibility tools. Run the code through Lighthouse or axe DevTools to catch common issues.
• Check keyboard navigation. Can users tab through elements properly? Is focus managed correctly?

5. Giving Unhelpful Feedback

Bad code reviews aren’t just about what you say, but how you say it. Vague comments like “this looks wrong” or “fix this” don’t help anyone, and overly harsh critiques can demoralize developers instead of helping them improve.

How to fix it:

• Be specific. Instead of “this is bad,” explain why: “This function is doing too many things—can we break it into smaller parts?”
• Ask questions. Instead of assuming something is wrong, ask for clarification: “Is there a reason we used useEffect here instead of an event listener?”
• Use a collaborative tone. Think of code reviews as discussions, not personal attacks. Frame feedback as suggestions, not orders.

6. Not Reviewing Tests (or Not Having Any at All)

A new feature without tests is a future bug waiting to happen. Yet, many developers skip reviewing test coverage or worse, ignore the fact that no tests were added.

How to fix it:

• Check if tests exist. If a new feature is added, does it have test coverage? If not, ask why.
• Ensure tests cover edge cases. Do the tests only check the happy path, or do they also account for errors and edge cases?
• Encourage meaningful tests. Avoid snapshot tests that just confirm markup hasn’t changed. Instead, focus on behavior-driven tests.

7. Not Considering Long-Term Maintainability

A piece of code might work today, but will it be easy to update six months from now? Will a new developer joining the team understand what it does?

How to fix it:

• Check for unnecessary complexity. Is this solution more complicated than it needs to be? Could it be simplified?
• Look for reusable patterns. Does this introduce duplicate code that could be extracted into a reusable component or function?
• Encourage documentation. If a piece of logic is non-obvious, suggest adding a comment or updating the documentation.

Final Thoughts

Code reviews should be about improving code, not just finding flaws. They’re a chance to share knowledge, spot potential issues early, and help the whole team level up.

By avoiding these common mistakes, focusing on what matters, giving constructive feedback, and thinking about long-term maintainability, you can make your code reviews more effective and enjoyable for everyone involved.