tessl/npm-js-beautify
A comprehensive code beautification library for JavaScript, CSS, and HTML with extensive formatting options and cross-platform support
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javascript.mddocs/
JavaScript Beautification
JavaScript code formatting with comprehensive support for modern JavaScript syntax, various brace styles, and advanced formatting options. Includes support for deobfuscation and unpacking of minified code.
Core Imports
// Import JavaScript beautifier
const { js_beautify } = require('js-beautify');
const beautify = require('js-beautify'); // beautify.js is the same as js_beautify
// Or use the short alias
const { js } = require('js-beautify');ESM:
import beautify from 'js-beautify';
// Use beautify.js() or just beautify() for JavaScriptCapabilities
JS Beautify Function
Beautifies JavaScript source code with extensive formatting control and syntax support.
/**
* Beautify JavaScript source code
* @param {string} js_source_text - JavaScript code to beautify
* @param {Object} options - Formatting options (optional)
* @param {string} [options.brace_style='collapse'] - Brace placement style: 'collapse', 'expand', 'end-expand', 'none', 'preserve-inline'
* @param {boolean} [options.unindent_chained_methods=false] - Don't indent chained method calls
* @param {boolean} [options.break_chained_methods=false] - Break chained method calls across subsequent lines
* @param {boolean} [options.space_in_paren=false] - Add padding spaces within parentheses
* @param {boolean} [options.space_in_empty_paren=false] - Add a single space inside empty parentheses
* @param {boolean} [options.jslint_happy=false] - Enable jslint-stricter mode
* @param {boolean} [options.space_after_anon_function=false] - Add space before anonymous function parentheses
* @param {boolean} [options.space_after_named_function=false] - Add space before named function parentheses
* @param {boolean} [options.keep_array_indentation=false] - Preserve array indentation
* @param {boolean} [options.space_before_conditional=true] - Add space before conditional statements
* @param {boolean} [options.unescape_strings=false] - Decode printable characters encoded in xNN notation
* @param {boolean} [options.e4x=false] - Pass E4X xml literals through untouched
* @param {boolean} [options.comma_first=false] - Put commas at the beginning of new line instead of end
* @param {string} [options.operator_position='before-newline'] - Set operator position relative to newlines: 'before-newline', 'after-newline', 'preserve-newline'
* @returns {string} Beautified JavaScript code
*/
function js_beautify(js_source_text, options);
/**
* Get default options for JavaScript beautifier
* @returns {Object} Default options object with all JavaScript-specific options
*/
js_beautify.defaultOptions();Default Options Function
Retrieve the default configuration options for JavaScript beautification.
/**
* Get default options for JavaScript beautifier
* @returns {Object} Default options object with all JavaScript-specific options
*/
js_beautify.defaultOptions();Usage Examples:
const beautify = require('js-beautify');
// Basic beautification
const uglyCode = 'function test(){var a=1;var b=2;return a+b;}';
const beautiful = beautify.js(uglyCode, { indent_size: 2 });
// Result:
// function test() {
// var a = 1;
// var b = 2;
// return a + b;
// }
// Advanced formatting with custom options
const complexCode = 'if(condition){doSomething();doSomethingElse();}else{doDefault();}';
const formatted = beautify.js(complexCode, {
indent_size: 4,
brace_style: 'expand',
space_before_conditional: true
});
// Chained method formatting
const chainedCode = 'obj.method1().method2().method3();';
const chainFormatted = beautify.js(chainedCode, {
break_chained_methods: true,
indent_size: 2
});Default Options
Returns the default configuration options for JavaScript beautification.
/**
* Get default options for JavaScript beautification
* @returns Default JSBeautifyOptions object
*/
function defaultOptions(): JSBeautifyOptions;Usage Example:
const beautify = require('js-beautify');
// Get default options
const defaults = beautify.js.defaultOptions();
console.log(defaults.indent_size); // 4
console.log(defaults.brace_style); // 'collapse'
// Modify defaults for custom configuration
const myOptions = {
...defaults,
indent_size: 2,
space_after_anon_function: true
};Brace Style Options
Collapse (Default)
Places opening braces on the same line as control statements.
if (condition) {
statement;
}Expand
Places opening braces on new lines.
if (condition)
{
statement;
}End-Expand
Like expand, but places closing braces on separate lines.
if (condition)
{
statement;
}None
Attempts to keep braces where they are.
Preserve-Inline
Preserve inline block braces and formatting (can be combined with other styles).
Operator Position Options
Before-Newline (Default)
Places operators before line breaks.
const result = value1 +
value2 +
value3;After-Newline
Places operators after line breaks.
const result = value1
+ value2
+ value3;Preserve-Newline
Preserves existing operator positioning.
Special Features
JSLint Compatibility
When jslint_happy is enabled, the formatter makes adjustments to be compatible with JSLint requirements:
- Forces
space_after_anon_functionto true - Adjusts various formatting rules to match JSLint expectations
E4X Support
When e4x is enabled, E4X (ECMAScript for XML) literals are passed through untouched, preserving their formatting.
String Unescaping
When unescape_strings is enabled, the beautifier will decode printable characters that were encoded in xNN notation.
Array Indentation
When keep_array_indentation is enabled, the original indentation of arrays is preserved even when it doesn't match the configured indent settings.