UglifyJS

What UglifyJS is

UglifyJS is a JavaScript toolkit for parsing, minifying, compressing and beautifying code. Developers can install it from npm and use it from the command line or in applications. The command-line interface accepts multiple input files and can read from standard input when no file is supplied. For programmatic use, its configurable `minify()` function processes JavaScript and can return minified code, warnings or errors.

The toolkit can generate source maps and compose mappings from compiled JavaScript back to original source files. It also includes AST utilities, can import SpiderMonkey AST input and can use Acorn as an optional parser. UglifyJS supports JavaScript and most ECMAScript features; its documentation recommends transpiling more exotic syntax with tools such as Babel first. Compatibility options are available for projects that need behavior beyond the defaults. The project also describes compiler assumptions and cautions that some transformations can change behavior in particular cases.

UglifyJS is free, BSD-licensed software for API, Linux and self-hosted use. Its command-line and programmatic interfaces are intended for developers incorporating it into build workflows or applications.

Who it suits

UglifyJS suits developers who need JavaScript parsing, minification, compression or beautification in a command-line workflow or application. Its API, source-map generation and AST utilities also support projects that need programmatic processing or mappings back to original source files.

Limits

The free plan is listed as free. The project recommends transpiling more exotic syntax first, and default compatibility behavior does not target Internet Explorer, Chrome/Node.js V8 or Safari/WebKit proofing.

Getting started

1. Install UglifyJS from npm.
2. Use the command-line tool with one or more input files, or provide input through standard input.
3. For programmatic use, call the configurable `minify()` function.
4. Use Acorn as an optional parser if needed.
5. Transpile more exotic syntax with a tool such as Babel before processing it.

Verdict

Choose UglifyJS if you need a free JavaScript toolkit with command-line and API options, source maps and AST utilities. Look elsewhere if your syntax needs exceed its supported features without transpilation, or if you need the defaults to target the compatibility environments it excludes.