File: README.md

# Uglifier [![Build Status](secure.travis-ci.org/lautis/uglifier.png?branch=master)](http://travis-ci.org/lautis/uglifier) [![Dependency Status](gemnasium.com/lautis/uglifier.png?travis)](https://gemnasium.com/lautis/uglifier)

Ruby wrapper for [UglifyJS](github.com/mishoo/UglifyJS2) JavaScript compressor.

## Installation

Uglifier is available as a ruby gem.

    $ gem install uglifier

Ensure that your environment has a JavaScript interpreter supported by [ExecJS](github.com/sstephenson/execjs). Using `therubyracer` gem is a safe choice if a runtime isn‘t already present. Note that while JScript built-in Windows 7 and older works, it is extremely slow.

## Usage

```ruby require ‘uglifier‘

Uglifier.new.compile(File.read("source.js")) # => js file minified

# Or alternatively Uglifier.compile(File.read("source.js")) ```

Uglifier also supports generating source maps:

```ruby uglified, source_map = Uglifier.new.compile_with_map(source) ```

When initializing UglifyJS, you can tune the behavior of UglifyJS by passing options. For example, if you want disable variable name mangling:

```ruby Uglifier.new(:mangle => false).compile(source)

# Or Uglifier.compile(source, :mangle => false) ```

Available options and their defaults are

```ruby {

  :output => {
    :ascii_only => false,       # Escape non-ASCII characters
    :comments => :copyright,    # Preserve comments (:all, :jsdoc, :copyright, :none)
    :inline_script => false,    # Escape occurrences of </script in strings
    :quote_keys => false,       # Quote keys in object literals
    :max_line_len => 32 * 1024, # Maximum line length in minified code
    :bracketize => false,       # Bracketize if, for, do, while or with statements, even if their body is a single statement
    :semicolons => true,        # Separate statements with semicolons
    :preserve_line => false,    # Preserve line numbers in outputs
    :beautify => false,         # Beautify output
    :indent_level => 4,         # Indent level in spaces
    :indent_start => 0,         # Starting indent level
    :space_colon => false,      # Insert space before colons (only with beautifier)
    :width => 80                # Specify line width when beautifier is used (only with beautifier)
  },
  :mangle => {
    :except => ["$super"]       # Argument names to be excluded from mangling
  },                            # Mangle variable and function names, set to false to skip mangling
  :compress => {
    :sequences => true,         # Allow statements to be joined by commas
    :properties => true,        # Rewrite property access using the dot notation
    :dead_code => true,         # Remove unreachable code
    :drop_debugger => true,     # Remove debugger; statements
    :unsafe => false,           # Apply "unsafe" transformations
    :conditionals => true,      # Optimize for if-s and conditional expressions
    :comparisons => true,       # Apply binary node optimizations for comparisons
    :evaluate => true,          # Attempt to evaluate constant expressions
    :booleans => true,          # Various optimizations to boolean contexts
    :loops => true,             # Optimize lops when condition can be statically determined
    :unused => true,            # Drop unreferenced functions and variables
    :hoist_funs => true,        # Hoist function declarations
    :hoist_vars => false,       # Hoist var declarations
    :if_return => true,         # Optimizations for if/return and if/continue
    :join_vars => true,         # Join consecutive var statements
    :cascade => true            # Cascade sequences
  },                            # Apply transformations to code, set to false to skip
  :define => {},                # Define values for symbol replacement
  :enclose => false,            # Enclose in output function wrapper, define replacements as key-value pairs
  :source_filename => nil,      # The filename of the input file
  :source_root => nil,          # The URL of the directory which contains :source_filename
  :output_filename => nil,      # The filename or URL where the minified output can be found
  :input_source_map => nil,     # The contents of the source map describing the input
  :screw_ie8 => false           # Generate safe code for IE8

} ```

## Development

Uglifier bundles its javascript dependencies using git submodules. If you want to rebuild the javascript you will first need to get the latest version of the code with `git submodule update —init`. After you have the git submodules at the desired versions, run `rake js` to recreate `lib/uglify.js`.

See [CONTRIBUTING](github.com/lautis/uglifier/blob/master/CONTRIBUTING.md) for details about contributing to Uglifier.

## Copyright