Code Formatter
Format JavaScript, TypeScript, HTML, CSS, and JSON with consistent indentation rules.
Note: This formatter applies basic indentation and structure normalization. For production-grade formatting with full AST-based rules, consider using Prettier locally.
Code formatting runs entirely in your browser. Your input is not sent to CodeAva servers and is not stored between sessions. Formatting improves code structure — it does not validate logic or check for security issues.
Overview
Code formatting is the process of applying consistent indentation, spacing, and structure to source code without changing its behaviour. It makes code easier to read, reduces cognitive load during review, and removes formatting debates from pull request discussions. This tool applies basic structural formatting to JavaScript, TypeScript, HTML, CSS, and JSON using rules you can adjust.
Formatting works by normalising whitespace and indentation rules: blocks are indented consistently, declarations are separated cleanly, and excess blank lines are removed. For JSON, the formatter uses the browser's native JSON.parse followed by JSON.stringify for reliable output. For HTML, CSS, JavaScript, and TypeScript, structural heuristics handle indentation based on braces, tags, and line structure.
This is a lightweight formatter suited for quick cleanup tasks. For production codebases with complex formatting requirements, a full AST-based tool like Prettier integrated into your editor or CI pipeline will give more precise and consistent results.
Use cases
When to use it
- Cleaning pasted codenormalize indentation on code copied from Stack Overflow, documentation, or a colleague's message.
- Preparing docs examplestidy up code snippets before including them in READMEs, wiki articles, or API documentation.
- Improving readability before debuggingformat minified or inconsistently indented code so you can read it before tracing through logic.
- Normalising team submissionsquickly clean up code before a review or discussion when you do not have a local formatter set up.
- Tidying config filesformat JSON, CSS, or HTML configuration files that have been hand-edited or generated without consistent spacing.
When it's not enough
- Linting for logic errorsformatting only adjusts whitespace and structure — it will not catch undefined variables, type errors, or business logic bugs.
- Replacing a proper code reviewformatted code is easier to read, but readability does not imply correctness.
- Assuming formatted code is validthe formatter may succeed even on syntactically broken code for some languages. Always verify output before using it.
- Complex TypeScript or advanced patternsthe JS/TS formatter uses simple heuristics. Complex generics, decorators, or nested template literals may not format cleanly — use Prettier locally for those cases.
How to use it
- 1
Select the language
Choose the language that matches your code: JavaScript, TypeScript, JSON, HTML, or CSS.
- 2
Set the indent size
Choose 2 or 4 spaces depending on your project's convention.
- 3
Paste your code
Add the unformatted or poorly indented code into the Input panel on the left.
- 4
Click Format
The formatted output appears in the right panel. If the input has a syntax error (especially for JSON), an error message is shown instead.
- 5
Copy the result
Use the copy button on the output panel to copy the formatted code to your clipboard.
Common errors and fixes
JSON format fails with a parse error
JSON must be syntactically valid before it can be formatted. Common issues are trailing commas, single-quoted strings, and missing closing brackets. Use the JSON Formatter tool for detailed error messages with position information.
HTML output has unexpected indentation
The HTML formatter uses tag-based heuristics. Inline elements mixed with block elements, or HTML that uses custom components or template syntax (like Jinja or Handlebars), may not indent as expected. For template-heavy HTML, use a dedicated tool.
JavaScript or TypeScript output looks wrong
The JS/TS formatter uses structural heuristics based on braces and semicolons. Minified code with no whitespace, complex nested arrow functions, or unusual patterns may not format cleanly. For production JS/TS formatting, use Prettier.
Format button does nothing
Check that the input panel is not empty. The formatter only runs when there is content to format. Also confirm you have selected the correct language for your input.
Output is formatted but still has inconsistent style
This tool applies basic indentation normalisation, not full style enforcement. For consistent style rules across a codebase — trailing commas, quote style, line length limits — you need Prettier or ESLint with a style config.