ChatGPT Prompt for Refactoring JavaScript Code

Use this ChatGPT prompt to refactor JavaScript code. Copy the template, paste your code, and get a cleaner, more maintainable version with an explanation of the changes.

Prompt Template

prompt.txt

You are a senior JavaScript engineer.

Refactor the following JavaScript code to improve:
1. Readability and clarity.
2. Maintainability and structure.
3. Performance where applicable.
4. Adherence to modern JavaScript best practices (ES6+).

For each change, add a brief inline comment explaining why the change was made.

Code:
[PASTE CODE HERE]

Open in ChatGPT Open in Claude

How to Use This Prompt

1Copy the prompt template above.
2Paste it into ChatGPT at chat.openai.com.
3Replace [PASTE CODE HERE] with the JavaScript code you want to refactor.
4Optionally specify constraints, e.g. "do not change the function signature".
5Review the refactored version and the explanation of each change.

When to Use This Prompt

You have legacy JavaScript code that is hard to maintain.
A code review flagged readability or complexity issues.
You want to modernise code written before ES6.
You are onboarding to a codebase and need to understand it better.

Example Input

function proc(d) {
  var r = [];
  for (var i = 0; i < d.length; i++) {
    if (d[i].a == true) {
      var obj = {};
      obj.n = d[i].name;
      obj.v = d[i].val * 2;
      r.push(obj);
    }
  }
  return r;
}

Expected Output

The AI will rewrite the function using const/let, arrow functions, array destructuring, and Array.filter/map, rename variables for clarity, and add comments explaining each modernisation decision.

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Frequently Asked Questions

Can ChatGPT refactor JavaScript code?

Yes. ChatGPT can refactor JavaScript to use modern ES6+ patterns, improve variable naming, reduce complexity, and apply cleaner functional patterns. It works well for both small functions and larger modules.

What JavaScript improvements does AI typically suggest?

Common improvements include replacing var with const/let, using arrow functions, adopting destructuring, converting loops to map/filter/reduce, removing unnecessary nesting, and applying consistent naming conventions.

Will AI refactoring change the behaviour of my code?

AI aims to produce functionally equivalent refactored code, but subtle behaviour differences can occur — especially around edge cases, type coercion, or scope. Always run your test suite after applying AI-suggested refactors.

Can I use this prompt for TypeScript as well?

Yes. Modify the prompt to say "TypeScript" instead of "JavaScript" and ask the AI to also add or improve type annotations. ChatGPT understands TypeScript well and will apply type-safe patterns.