Uglifyrb

Ruby wrapper for UglifyJS JavaScript compressor.

Installation

Ensure that your environment has UglifyJS CLI.

Add this line to your application's Gemfile:

gem 'uglifyrb'

And then execute:

$ bundle

Or install it yourself as:

$ gem install uglifyrb

Usage

require 'uglifyrb'

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

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

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

Uglifyrb.new(:mangle => false).compile(source)

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

Available options and their defaults are

{
  :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 </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)
    :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
  :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
    :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_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,          # Don't bother to generate safe code for IE8
  :source_map_url => false,     # Url for source mapping to be appended in minified source
  :source_url => false          # Url to original source to be appended in minified source
}

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/malida/uglifyrb. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.