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DevCodivo

JavaScript Formatter

Beautify JavaScript — consistent indentation, spacing and brace styles.

Runs in your browser — your data never leaves your deviceFree, no sign-up
Options
Formatted JavaScript

The formatted JavaScript will appear here.

How it works

Your code is processed by the JavaScript mode of js-beautify — the library behind most beautifier tools. Blocks are indented one level deeper than their parents, operators get consistent spacing, object literals and arrays are split across lines, and chain links like .map().filter() are broken onto separate lines when long.

Your code is never executed or evaluated — only analyzed as text.

Features

  • Consistent indentation and operator spacing
  • Three brace styles: K&R, Allman, end-expand
  • Objects, arrays and chains split readably
  • Code never executed or evaluated — text analysis only
  • 100% client-side — nothing leaves your browser

How to use

  1. Paste JavaScript, or upload a .js file.
  2. Choose indentation and brace style.
  3. Press Format JavaScript, then copy the result or download it as a .js file.

Example

Input:  const x={a:1,b:[1,2]};
Output: const x = {
          a: 1,
          b: [1, 2]
        };

Frequently asked questions

Does the formatter validate my JavaScript?
No — it is a formatter, not a validator, and it never executes your code. It re-indents and re-flows tokens without checking the syntax, so broken code may still produce output. Use it to make code readable, not to check it runs — for that, use a linter or run the code.
Is my code executed or evaluated in any way?
No. The formatter only analyzes the text of your code to place line breaks and indentation. It never runs, compiles or evaluates it — there is no eval, no Function constructor, no execution of any kind. This is a hard security rule for this site.
What do the brace style options mean?
Collapse (K&R style, the default) puts the opening brace on the same line as the statement — function foo() {. Expand (Allman style) puts it on its own line. End-expand puts closing braces on their own line but keeps opening braces attached. Pick whichever matches your project's style guide.
Can it format TypeScript?
Partially. The formatter treats input as JavaScript, so TypeScript-specific syntax (type annotations, interfaces, generics) is passed through unformatted rather than understood. Plain JavaScript formats perfectly; TypeScript comes out readable but not fully re-indented.
Does formatting change what my code does?
No. Only whitespace and line breaks change — tokens, strings, comments and logic are left exactly as you wrote them. Automatic semicolon insertion can, however, make some previously-ambiguous line breaks meaningful, which is one more reason every statement should end with a semicolon.
Is my code sent to a server?
No. Formatting happens entirely in your browser with JavaScript. Nothing you type is transmitted anywhere — you can verify this in your browser's network inspector.

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