# Uglifier Ruby wrapper for [UglifyJS](https://github.com/mishoo/UglifyJS2) JavaScript compressor. [![Build Status](https://travis-ci.org/lautis/uglifier.svg?branch=master)](https://travis-ci.org/lautis/uglifier) ## Installation Uglifier is available as a ruby gem. $ gem install uglifier Ensure that your environment has a JavaScript interpreter supported by [ExecJS](https://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 => true, # Escape non-ASCII characters :comments => :copyright, # Preserve comments (:all, :jsdoc, :copyright, :none, Regexp (see below)) :inline_script => false, # Escape occurrences of 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) :preamble => nil # Preamble for the generated JS file. Can be used to insert any code or comment. }, :mangle => { :eval => false, # Mangle names when eval of when is used in scope :except => ["$super"], # Argument names to be excluded from mangling :sort => false, # Assign shorter names to most frequently used variables. Often results in bigger output after gzip. :toplevel => false # Mangle names declared in the toplevel scope }, # Mangle variable and function names, set to false to skip mangling :mangle_properties => { :regex => nil # A regular expression to filter property names to be mangled } # Mangle property names, disabled by default :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 loops 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 :collapse_vars => false, # Collapse single-use var and const definitions when possible. :negate_iife => true, # Negate immediately invoked function expressions to avoid extra parens :pure_getters => false, # Assume that object property access does not have any side-effects :pure_funcs => nil, # List of functions without side-effects. Can safely discard function calls when the result value is not used :drop_console => false, # Drop calls to console.* functions :angular => false, # Process @ngInject annotations :keep_fargs => false, # Preserve unused function arguments :keep_fnames => false # Preserve function names }, # 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_map => { :map_url => false, # Url for source mapping to be appended in minified source :url => false, # Url for original source to be appended in minified source :sources_content => false, # Include original source content in map :filename => nil, # The filename of the input file :root => nil, # The URL of the directory which contains :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 } } ``` When passing a regular expression to the output => comments option, be sure to pass a valid Ruby Regexp. The beginning and ending of comments are removed and cannot be matched (/*, */, //). For example: When matching ``` /*! * comment */ ``` use `Uglifier.new(output: {comments: /^!/})`. ## Development Tests are run using bundle exec rake See [CONTRIBUTING](https://github.com/lautis/uglifier/blob/master/CONTRIBUTING.md) for details about working on and contributing to Uglifier. ## Copyright © Ville Lautanala. Released under MIT license, see [LICENSE](https://github.com/lautis/uglifier/blob/master/LICENSE.txt) for details.