Format and beautify minified JavaScript code with configurable indentation and brace style options.
JavaScript Beautifier turns compact or irregular JavaScript into a consistently spaced, line-broken version. It separates statements, indents nested blocks, spaces punctuation and operators, and places braces according to the selected style. The indentation setting controls how far each nesting level moves to the right. The result is still JavaScript source, not an explanation or a rewritten program. A common surprise is that beautification cannot restore meaningful identifier names, comments, or source structure removed during minification, and readable output does not prove that the code is correct or safe.
A concrete input and expected output from the current implementation.
Input
function add(a,b){return a+b;} Expected output
function add(a, b) {
return a + b;
} With two-space indentation and opening braces kept on the same line, the function body moves one level inward. Spaces are added after the parameter comma and around the + operator, while the function's operation remains unchanged.
The beautifier reorganizes ordinary whitespace around commas, operators, parentheses, statements, and block boundaries. Line breaks and indentation expose the nesting of functions, conditionals, loops, object literals, and other JavaScript constructs. Literal content, such as characters inside quoted strings, must remain distinct from the surrounding formatting. The returned value is JavaScript source text suitable for copying and reviewing.
Indentation controls the leading whitespace assigned to each nested level. Brace style controls whether an opening brace remains beside a function or control statement or appears on a separate line. These settings affect presentation rather than requesting a refactor: choosing another style does not change which statements belong to a block or recover structure absent from the supplied source.
No. It can reveal blocks, statements, operators, and nesting by restoring conventional spacing and line breaks. It cannot infer the author's original variable names, reconstruct deleted comments, split bundled modules back into their source files, or undo transformations that changed program structure. A source map, when separately available, is the appropriate artifact for relating generated code to original sources.
Equivalent behavior is the intended result for valid JavaScript, but formatting alone is not a proof of equivalence. JavaScript grammar gives line terminators special significance in several contexts, including automatic semicolon insertion. Test the result before replacing production code, particularly when the input is malformed, uses unusual whitespace boundaries, or depends on generated syntax that is difficult to inspect manually.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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