Developer Checklist: 18 Tips for Perfect React Code Review (TS/JS)

How to Perform a React Code Review?

Have you ever opened a PR and thought, “What am I even looking for?”

A React code review is a crucial element of the development process. On its own, it can improve code quality, catch bugs, and keep the team aligned with project changes. 

If you’re struggling with reviewing code or haven’t done it before, this article is the perfect place. I’ll share the ways our team at Pagepro keeps the reviews smooth and informative, what you should look for during the process, and how to write good statements instead of unnecessary comments.

Curious how strong teamwork shapes great development? Watch our video on leading successful Next.js teams.

What Is the Goal of Code Review?

Detecting bugs is an important aspect of code reviews. However, the main focus should be on knowledge sharing and boosting the confidence of the developer whose JavaScript code is being reviewed. Accepting a pull request should be seen as recognition of a job well done, reinforcing a positive team environment. 

A good code review should include:

• A showcase of changes made to the project, to keep the team informed about the development of React components.
• Feedback and knowledge sharing with teammates.
• Mentoring less experienced developers on writing efficient code according to Reactjs best practices.
• Establishing a solid understanding of the project.
• Discussions on alternative solutions with fellow frontend developers.
• Exploring different approaches to problem-solving.
• Identifying and addressing potential issues or bugs in the project or its UI.

Before You Start: Best Practices for Code Review

The first thing to do during a review is to set up some ground rules. They’ll help you avoid potential frustration and stress. 

Here are the rules for an effective code review I’ve set up for myself and my team:

Rule 1: Lint the Code Before Submission

Linting is the process of analyzing code to identify potential errors, coding style violations, and other issues. It helps ensure high-quality code, spot bugs early, and promotes consistent coding standards across the project. If developers actively run linting and fix issues before submitting their code, it makes the review process easier for the team.

Rule 2: Self-Review Before Submitting

Developers should review their code directly on the platform before sharing the link with a reviewer, since it helps catch unnecessary comments, console.log statements, formatting issues, and other leftovers.

Rule 3: Include a Description of Changes in the Pull Request

A summary helps the reviewer understand the context. It doesn’t need to be overly detailed, just enough to give context:

“Added a new player listing page with a table. The table includes pagination but isn’t sortable or filterable yet. Using mock data for now since the API isn’t ready.”

Rule 4: Attach Screenshots of the Work Done

Sometimes it’s a good idea to send some screenshots, so the reviewer doesn’t have to run the project (unless they have to test it).

Rule 5: Make Comments Visible

Keep comments public to avoid miscommunication or lost feedback. Transparency is an important factor in building trust, but having everyone on the same page about suggested changes is just as valuable. 

Rule 6: Indicate the Time

Even experienced React developers sometimes wait for reviews before starting new work. Once you receive a code for a review, let the developer know when you’ll be able to take care of it, and if you are too busy for an in-depth check, mention it too.

“I had only 15 minutes, so I just quickly checked the most important things like A, B, C.”.

Rule 7: Don’t Waste Time on Styling Issues

In my experience, most comments during code checks are about styling issues. If you encounter styling concerns throughout the React codebase, address them once and propose solutions, so you can avoid repetitive comments on each request.

Rule 8: Avoid Pull Requests with Too Many Files

The more files in a PR, the fewer comments it will get, since no software developer has time to review hundreds of changes in detail. If a feature is large, create a separate branch for it and break it into smaller sub-branches with focused changes.

Feel free to set up your own rules the way you want, and once you do, it’s time to start the review.

How to Give Constructive Feedback

Like in a real conversation, how and when you deliver your feedback is very important.

Don’t just demand changes; explain why they’re necessary so the engineer whose code you’re reviewing can learn from the process. Offer praise where it’s due to keep your teammates motivated.

Remember, not all code reviews are the same. Your approach should depend on how familiar you are with the development process.

Working in the Same Dev Team

If you’re a React developer reviewing code within your project, both you and the developer requesting the review benefit from the process.

As the reviewer, you’ll stay updated on changes in the codebase, making it easier to spot potential issues early. You can quickly catch bugs in functional components, ensure backward compatibility, and correct any incorrect method usage before these issues grow into bigger problems.

Additionally, reviewing code allows you to share useful code patterns with the rest of the team, helping everyone learn and improve together.

Reviewing External React.js Code

If you’re checking the code you haven’t actively worked on, don’t worry about missing certain details. You’re not expected to catch every functionality or code structure issue.

In this situation, spotting bugs can be more challenging, so if you do find one, great! However, ask for clarification if you need to. Approach the review with curiosity to better understand the reasoning behind the decisions. Once you spot a bug, address it once and propose solutions to avoid repetitive comments on each request.

No matter how familiar you are with the code, always remember to keep the communication open among team members! Even a quick message like, “Hey, I left some comments in your PR. Let me know if you have any questions!” helps things stay collaborative.

Organize Your Comments

A good way to keep feedback clear and constructive is to categorize comments into three types:

• Major: These are critical issues that must be fixed before merging. They could break the app, cause regressions, or fail to meet requirements.
• Minor: Suggestions for improving code readability, reusability, or general quality. If the developer has a solid reason for their approach, it’s okay to leave things as they are.
• Optional: Small tweaks like formatting or syntax updates that don’t affect functionality.

18 Tips for a Better React Code Review

Here’s the full checklist overview of our tips and what to check to do a better review and create React applications front-end developers can be proud of:

• Step 1: Review New Dependencies: Check if any new npm packages were added and assess their necessity to make the code clear and maintainable.
• Step 2: Avoid Library Duplicates: Ensure no redundant libraries are doing the same job (e.g., date-fns + moment).
• Step 3: Verify Import Practices: Look out for non-optimized imports that may break tree shaking:

import _ from 'lodash';
//should became more precise import like:
import uniq from 'lodash/uniq'; 

Step 4: Validate Translations: Make sure newly added areas are properly localized:

const NewComponent = () => {
  return (
    <div>
      New static text inside new component should be translated!
    </div>
  )
}

• Step 5: Enforce Proper Typing: If you are using TypeScript, all ANY types should also be fixed unless you have a really, really good explanation for not doing so. Below, we have missing props types and any in the method.

const NewComponent = ({items, data}) => {
  const getItemId = (data: any) => data.id
  return (
    <div>
      {items.map(item => (
        <span key={getItemId(item)}>
          <h1>{item.title}</h1>
          <p>{item.description}</p>
        </span>
      ))}
    </div>
  )
}

• Step 6: Check Naming Conventions: Variables and functions should have clear and descriptive names.
• Step 7: Use Boolean Prefixes: Use is, are, or should to clarify boolean intent.
• Step 8: Reflect Function Intent: Function names should explain what they do or return.
• Step 9: Watch for Overcomplicated Logic: Point out places where code can be simplified.
• Step 10: Simplify Verbose Code: Refactor unnecessarily long solutions into simpler alternatives.
• Step 11: Ask About Ambiguous Code: If logic is unclear, request a developer’s explanation.
• Step 12: Avoid Hardcoded Values: Move paths, names, and values into constants or configs.
• Step 13: Maintain Backward Compatibility: Look for changes that might break existing usage.
• Step 14: Eliminate Repetitive Logic: Flag repeated patterns that could be extracted into reusable functions.
• Step 15: Check Form Validations: Ensure form fields are validated and rules are correct.
• Step 16: Catch API Errors Gracefully: Look for missing or unhandled try/catch blocks.
• Step 17: Optimize Async Logic: Confirm that async tasks are handled efficiently and correctly.
• Step 18: Apply Past Lessons: Use your own past dev experience to guide code improvements.

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Best Code Quality with React Code Review

Even if you’re one of ten software engineers reviewing the code of a React app, it’s still your responsibility. A good review process helps everyone improve and keeps collaboration productive.

Set some ground rules to keep reviews consistent and clear. If you see an issue and know how to fix it, suggest a solution, but explain your feedback instead of just giving orders. A little context goes a long way, so instead of “Change A to B,” say “Could we rename A to B since it updates multiple fields?” 

And most importantly, notice the good stuff, not just the problems! Giving a shout-out to a well-structured code or a smart approach keeps the morale of the team up.

FAQ

How to Check Code Quality in React?

To check code quality in React, look at both the general software principles and React-specific best practices. Start by reviewing readability, consistent formatting, proper naming conventions, and the absence of dead or commented-out code. Then comb through React-specific areas like:

• Correct use of hooks (useEffect, useState, etc.)
• Clean JSX with clear render logic
• Proper prop and state handling
• Type safety (using TypeScript or PropTypes)
• Component modularity and reusability
• Performance optimizations (e.g., avoiding unnecessary re-renders)

What Tools Can I Use for a Better Code Review?

Tools like ESLint, Prettier, TypeScript, and unit tests can help improve your review process.

Where Can I Practice Reviewing Code?

The best places to practice and get feedback are:

• GitHub: Browse open-source React projects and look through pull requests. Many allow or encourage constructive feedback.
• Code Review Challenges: Sites like PullRequest Practice or Exercism can help simulate code review scenarios.
• Peer Review at Work: Offer to review a teammate’s code or ask to pair-review with a senior developer.
• Side Projects & Communities: Join developer communities on Discord or Reddit where people ask for feedback on their work.

Observe how others write and structure their code, and practice giving clear, helpful feedback.

How to Review React Code?

Reviewing code involves a mix of general and React-specific checks:

• Read the PR description or issue ticket to get context.
• Scan general code quality.
• Review component structure. Separate logic from presentation, and make sure components aren’t overloaded.
• Hooks should follow the rules, and side effects are handled correctly.
• Validate props and state. Props should be minimal, typed, and meaningful; state should not be misused.
• Look for performance issues to avoid unnecessary re-renders.
• Ensure the markup is accessible.
• Confirm proper testing, error handling, and responsiveness.
• End by leaving constructive, respectful feedback.

Read More

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