minify.js

June 10, 2026 · View on GitHub

</> minify.js

Recursively minify all JavaScript files.

⚡ Installation

As a global utility:

$ npm install -g @adamlui/minify.js

As a dev dependency (e.g. for build scripts), from your project root:

$ npm install -D @adamlui/minify.js

As a runtime dependency (e.g. for on-the-fly minification), from your project root:

$ npm install @adamlui/minify.js

💻 Command line usage

The basic global command is:

$ minify-js

📝 Note: Pass -n or --dry-run to only see what files will be processed.

To specify input/output paths:

$ minify-js [input_path] [output_path]

[input_path]: Path to JS file or directory containing JS files to be minified, relative to the current working directory.
[output_path]: Path to file or directory where minified files will be stored, relative to input root (if not provided, min/ is used).

📝 Note: If folders are passed, files will be processed recursively unless -R or --no-recursion is passed.

To use as a package script, in your project's package.json:

  "scripts": {
    "build:js": "<minify-js-cmd>"
  },

Replace <minify-js-cmd> with minify-js + optional args. Then, npm run build:js can be used to run the command.

Example commands

Minify all JavaScript files in the current directory (outputs to min/):

$ minify-js

Minify all JavaScript files in a specific directory (outputs to min/path/to/your/directory/):

$ minify-js path/to/your/directory

Minify a specific file (outputs to min/path/to/your/file.min.js):

$ minify-js path/to/your/file.js

Specify both input and output directories (outputs to output_folder/):

$ minify-js input_folder output_folder

Command line options

Boolean options:
 -n, --dry-run                        Don't actually minify the file(s), just show if they will be processed.
 -d, --include-dotfolders             Include dotfolders in file search.
 -D, --include-dotfiles               Include dotfiles in file search.
 -R, --no-recursion                   Disable recursive file searching.
 -M, --no-mangle                      Disable mangling names.
 -X, --no-filename-change             Disable changing file extension to .min.js
 -i, --rewrite-imports                Update import paths from .js to .min.js
 -c, --copy                           Copy minified code to clipboard instead of writing to file if single source file is processed.
 -r, --relative-output                Output files relative to each source file instead of to input root.
 -q, --quiet                          Suppress all logging except errors.

Parameter options:
 --ignores="dir/,file1.js,file2.js"   Files/directories to exclude from minification.
 --comment="comment"                  Prepend header comment to minified code. Separate by line using '\n'.
 --ui-lang="code"                     ISO 639-1 code of language to display UI in.
 --config="path/to/file"              Load custom config file.

Commands:
     --init                           Create config file (in project root).
 -h, --help                           Display help screen.
 -v, --version                        Show version number.
     --stats                          Show npm stats.
     --debug [targetKey]              Show debug logs.

Configuration file

minify.js can be customized using a minify.config.mjs or minify.config.js placed in your project root.

Example defaults:

export default {
    dryRun: false,            // don't actually minify the file(s), just show if they will be processed
    includeDotFolders: false, // include dotfolders in file search
    includeDotFiles: false,   // include dotfiles in file search
    noRecursion: false,       // disable recursive file searching
    noMangle: false,          // disable mangling names
    noFilenameChange: false,  // disable changing file extension to .min.js
    rewriteImports: false,    // update import paths from .js to .min.js
    copy: false,              // copy minified code to clipboard instead of write to file if single file processed
    relativeOutput: false,    // output files relative to each src file instead of to input root
    quietMode: false,         // suppress all logging except errors
    ignores: '',              // files/dirs to exclude from minification
    comment: ''               // header comment to prepend to minified code
}

💡 Run minify-js init to generate a template minify.config.mjs in your project root.

🔌 API usage

You can also import minify.js into your app to use its API methods, both as an ECMAScript module or a CommonJS module.

ESM*:

import minifyJS from '@adamlui/minify.js'

CJS:

const minifyJS = require('@adamlui/minify.js')

*Node.js version 14 or higher required

`minify(input[, options])`

💡 Minifies JavaScript code based on the string input supplied.

If source code is passed, it is directly minified, then an object containing srcPath + code + error is returned:

const srcCode = 'function add(first, second) { return first + second }',
      minifyResult = minifyJS.minify(srcCode)

console.log(minifyResult.error) // outputs runtime error, or `undefined` if no error
console.log(minifyResult.code)  // outputs minified JS: 'function add(n,d){return n+d}'

If a file path is passed, the file's code is loaded then minified, returning an object like above.

If a directory path is passed, JavaScript files are searched for (recursively by default), each one's code is loaded then minified, then an array of objects containing srcPath + code + error is returned:

// Outputs paths to source JS files in working directory + all nested directories
const minifyResults = minifyJS.minify('.')
minifyResults.forEach(result => console.log(result.srcPath))

// Outputs minified code of 2nd JS file if found, or `undefined` if not found
console.log(minifyResults[1].code)

Options are boolean, passed as object properties. For example:

// Returns data object where dotfiles are also processed if `input` is a path
minifyJS.minify(input, { dotFiles: true })

Available parameters (and their default settings) are:

Name	Type	Desciption	Default value
`recursive`	Boolean	Recursively search for nested files if dir path passed.	`true`
`verbose`	Boolean	Show logging in console/terminal.	`true`
`dotFolders`	Boolean	Include dotfolders in file search.	`false`
`dotFiles`	Boolean	Include dotfiles in file search.	`false`
`mangle`	Boolean	Shorten variable names (typically to one character).	`true`
`rewriteImports`	Boolean	Update import paths from .js to .min.js	`false`
`relativeOutput`	Boolean	Output files relative to each source file instead of to input root.	`false`
`ignores`	Array	Files/dirs to exclude from minification.	`[]`
`comment`	String	Header comment to prepend to minified code. Separate by line using '\n'.	`''`

`findJS(searchDir[, options])`

💡 Searches for all unminified JavaScript files within the searchDir string passed (useful for discovering what files minify() will process) and returns an array containing their filepaths.

Options are boolean, passed as object properties. For example:

// Search for unminified JS files in exactly assets/js:
const searchResults = minifyJS.findJS('assets/js', { recursive: false })
console.log(searchResults)

/* sample output:

findJS() » Searching for unminified JS files...
findJS() » Search complete! 2 files found.
findJS() » Check returned array.
[
  'E:\\js\\utils\\minify.js\\assets\\js\\foo.js',
  'E:\\js\\utils\\minify.js\\assets\\js\\bar.js'
]
*/

Available parameters (and their default settings) are:

Name	Type	Desciption	Default value
`recursive`	Boolean	Recursively search for nested files in searchDir passed.	`true`
`verbose`	Boolean	Show logging in console/terminal.	`true`
`dotFolders`	Boolean	Include dotfolders in file search.	`false`
`dotFiles`	Boolean	Include dotfiles in file search.	`false`
`ignores`	Array	Files/dirs to exclude from search results.	`[]`

🏛️ MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

🧠 Contributors

All contributions are very welcome!

{ } scss-to-css

Recursively compile all SCSS files into minified CSS.
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