JavaScript formatter
Format JavaScript without executing it.
JavaScript formatter
How to use JavaScript formatter
JavaScript formatter reformats code with consistent indentation, spacing, semicolons and double-quoted strings, without running it. The indent size can be set from 1 to 8 spaces. JSX syntax is also understood. Code with a syntax error returns the parser error rather than formatted output.
- Paste the source into the input editor, or load the built-in example.
- Set indent spaces.
- Run javascript formatter, review the output, then use the available copy or download controls.
What this tool supports
Format JavaScript without executing it.
- Indent spaces
- Range: 1 to 8
Limits and processing
Text operations generally accept up to 2,000,000 characters. Individual parsers, generators and formulas apply additional limits shown by their controls.
Example source
const greet=(name)=>{return `Hello ${name}`;}Frequently asked questions
Does the JavaScript formatter execute my code?
No. The code is parsed into a syntax tree and printed back with new formatting. It is never evaluated or run at any point.
Does the JavaScript formatter change quotes and semicolons?
Yes. Statements end with semicolons and single-quoted strings are rewritten with double quotes, following standard Prettier style. Template literals keep their backticks.
Can I format JSX with this tool?
Yes. JSX elements in JavaScript are recognized and formatted, with attribute quotes normalized. Invalid syntax returns the parser error message so you can locate the problem.
Where is my input processed?
This operation processes its source in your browser. Copy and download are explicit actions; source input is not saved in an account or history.
What are the input limits?
Text operations generally accept up to 2,000,000 characters. Individual parsers, generators and formulas apply additional limits shown by their controls.