Compare JavaScript and TypeScript Code Online — Free Side-by-Side Diff

JavaScript and TypeScript diffs come up constantly: comparing a function before and after adding TypeScript types, reviewing a refactor from callbacks to async/await, or checking what changed in a React component between versions.

Raven Code Diff supports both JavaScript and TypeScript with separate language selections. Paste your code, pick your language, and get a color-coded diff that makes keyword and syntax changes easy to spot.

JavaScript vs TypeScript Diffs — What to Watch For

When comparing JavaScript and TypeScript code, different changes carry different risks:

• Type annotation additions: Moving from JS to TS, adding : string, : number, or interface definitions — these are additive and generally safe
• Logic changes: Modified conditions, changed variable assignments, restructured control flow — these matter regardless of language
• Async/await vs callbacks: Converting callback-based code to promises changes the execution model even if the intent is the same
• Destructuring changes: What looks like a minor syntax change can affect which properties are extracted from an object
• Optional chaining added/removed: The difference between obj.a.b and obj?.a?.b is a null-safety question

Syntax highlighting helps here because it colors keywords differently from variable names, making structural changes more visible.

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How to Compare JavaScript or TypeScript Code

1. Open Raven Code Diff
2. Paste the original code (left panel) and modified code (right panel)
3. Select JavaScript or TypeScript from the language dropdown — they have separate options
4. Click Compare

The TypeScript option highlights TypeScript-specific syntax: type annotations, interface declarations, generic parameters, and decorators. Selecting TypeScript instead of JavaScript ensures those constructs are colored correctly rather than treated as unknown syntax.

Common JavaScript and TypeScript Comparison Scenarios

• Migration to TypeScript: Comparing the original .js and the new .ts version to verify logic wasn't changed during type annotation
• Refactoring review: Before/after a cleanup to check nothing functional changed
• Framework migration: Comparing a jQuery-based component with its React equivalent
• Dependency updates: Checking how a function needs to change after an API changed in a library update
• Code review: Isolating a specific component diff during a PR review

If you want to understand what a piece of JavaScript or TypeScript code actually does before comparing versions, our free AI code explainer handles JS and TS and gives plain-English explanations at beginner, intermediate, or expert level.

Frequently Asked Questions

Can I compare TypeScript code online for free?

Yes. Raven Code Diff has TypeScript as a separate language option with TypeScript-specific syntax highlighting (types, interfaces, generics). Paste both TypeScript snippets, select TypeScript, and click Compare.

How do I diff JavaScript files without VS Code?

Open Raven Code Diff in your browser, paste the contents of both JavaScript files, select JavaScript as the language, and click Compare. You get a side-by-side syntax-highlighted diff without opening VS Code or any desktop app.