# encoding: UTF-8
require "json"
require "execjs"
require "uglifier/version"
# A wrapper around the UglifyJS interface
class Uglifier
# Error class for compilation errors.
class Error < StandardError; end
# UglifyJS source path
SourcePath = File.expand_path("../uglify.js", __FILE__)
# UglifyJS with Harmony source path
HarmonySourcePath = File.expand_path("../uglify-harmony.js", __FILE__)
# Source Map path
SourceMapPath = File.expand_path("../source-map.js", __FILE__)
# ES5 shims source path
ES5FallbackPath = File.expand_path("../es5.js", __FILE__)
# String.split shim source path
SplitFallbackPath = File.expand_path("../split.js", __FILE__)
# UglifyJS wrapper path
UglifyJSWrapperPath = File.expand_path("../uglifier.js", __FILE__)
# Default options for compilation
DEFAULTS = {
# rubocop:disable Layout/LineLength
:output => {
:ascii_only => true, # 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
: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.
:wrap_iife => false, # Wrap IIFEs in parenthesis. Note: this disables the negate_iife compression option.
:shebang => true, # Preserve shebang (#!) in preamble (shell scripts)
:quote_style => 0, # Quote style, possible values :auto (default), :single, :double, :original
:keep_quoted_props => false # Keep quotes property names
},
:mangle => {
:eval => false, # Mangle names when eval of when is used in scope
:reserved => ["$super"], # Argument names to be excluded from mangling
:properties => false, # Mangle property names
: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
:unsafe_comps => false, # Reverse < and <= to > and >= to allow improved compression. This might be unsafe when an at least one of two operands is an object with computed values due the use of methods like get, or valueOf. This could cause change in execution order after operands in the comparison are switching. Compression only works if both comparisons and unsafe_comps are both set to true.
:unsafe_math => false, # Optimize numerical expressions like 2 * x * 3 into 6 * x, which may give imprecise floating point results.
:unsafe_proto => false, # Optimize expressions like Array.prototype.slice.call(a) into [].slice.call(a)
: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 (simple direct variable assignments do not count as references unless set to `"keep_assign"`)
:toplevel => false, # Drop unreferenced top-level functions and variables
:top_retain => [], # prevent specific toplevel functions and variables from `unused` removal
: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
:collapse_vars => true, # Collapse single-use var and const definitions when possible.
:reduce_funcs => false, # Inline single-use functions as function expressions. Depends on reduce_vars.
:reduce_vars => false, # Collapse variables assigned with and used as constant values.
: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
:keep_fargs => false, # Preserve unused function arguments
:keep_fnames => false, # Do not drop names in function definitions
:passes => 1, # Number of times to run compress. Raising the number of passes will increase compress time, but can produce slightly smaller code.
:keep_infinity => false, # Prevent compression of Infinity to 1/0
:side_effects => true, # Pass false to disable potentially dropping functions marked as "pure" using pure comment annotation. See UglifyJS documentation for details.
:switches => true # de-duplicate and remove unreachable switch branches
}, # Apply transformations to code, set to false to skip
:parse => {
:bare_returns => false, # Allow top-level return statements.
:expression => false, # Parse a single expression, rather than a program (for parsing JSON).
:html5_comments => true, # Ignore HTML5 comments in input
:shebang => true, # support #!command as the first line
:strict => false
},
:define => {}, # Define values for symbol replacement
:keep_fnames => false, # Generate code safe for the poor souls relying on Function.prototype.name at run-time. Sets both compress and mangle keep_fanems to true.
:toplevel => false,
:ie8 => true, # Generate safe code for IE8
:source_map => false, # Generate source map
:error_context_lines => 8, # How many lines surrounding the error line
:harmony => false # Enable ES6/Harmony mode (experimental). Disabling mangling and compressing is recommended with Harmony mode.
}
# rubocop:enable Layout/LineLength
EXTRA_OPTIONS = [:comments, :mangle_properties]
MANGLE_PROPERTIES_DEFAULTS = {
:debug => false, # Add debug prefix and suffix to mangled properties
:regex => nil, # A regular expression to filter property names to be mangled
:keep_quoted => false, # Keep quoted property names
:reserved => [], # List of properties that should not be mangled
:builtins => false # Mangle properties that overlap with standard JS globals
}
SOURCE_MAP_DEFAULTS = {
: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
}
# Minifies JavaScript code using implicit context.
#
# @param source [IO, String] valid JS source code.
# @param options [Hash] optional overrides to +Uglifier::DEFAULTS+
# @return [String] minified code.
def self.compile(source, options = {})
new(options).compile(source)
end
# Minifies JavaScript code and generates a source map using implicit context.
#
# @param source [IO, String] valid JS source code.
# @param options [Hash] optional overrides to +Uglifier::DEFAULTS+
# @return [Array(String, String)] minified code and source map.
def self.compile_with_map(source, options = {})
new(options).compile_with_map(source)
end
# Initialize new context for Uglifier with given options
#
# @param options [Hash] optional overrides to +Uglifier::DEFAULTS+
def initialize(options = {})
# rubocop:disable Lint/UnreachableLoop
(options.keys - DEFAULTS.keys - EXTRA_OPTIONS)[0..1].each do |missing|
raise ArgumentError, "Invalid option: #{missing}"
end
# rubocop:enable Lint/UnreachableLoop
@options = options
end
# Minifies JavaScript code
#
# @param source [IO, String] valid JS source code.
# @return [String] minified code.
def compile(source)
if @options[:source_map]
compiled, source_map = run_uglifyjs(source, true)
source_map_uri = [source_map].pack('m0')
source_map_mime = "application/json;charset=utf-8;base64"
compiled + "\n//# sourceMappingURL=data:#{source_map_mime},#{source_map_uri}"
else
run_uglifyjs(source, false)
end
end
alias_method :compress, :compile
# Minifies JavaScript code and generates a source map
#
# @param source [IO, String] valid JS source code.
# @return [Array(String, String)] minified code and source map.
def compile_with_map(source)
run_uglifyjs(source, true)
end
private
def context
@context ||= begin
source = harmony? ? source_with(HarmonySourcePath) : source_with(SourcePath)
ExecJS.compile(source)
end
end
def source_map_comments
return '' unless @options[:source_map].respond_to?(:[])
suffix = ''
if @options[:source_map][:map_url]
suffix += "\n//# sourceMappingURL=" + @options[:source_map][:map_url]
end
suffix += "\n//# sourceURL=" + @options[:source_map][:url] if @options[:source_map][:url]
suffix
end
def source_with(path)
[ES5FallbackPath, SplitFallbackPath, SourceMapPath, path,
UglifyJSWrapperPath].map do |file|
File.open(file, "r:UTF-8", &:read)
end.join("\n")
end
# Run UglifyJS for given source code
def run_uglifyjs(input, generate_map)
source = read_source(input)
input_map = input_source_map(source, generate_map)
options = {
:source => source,
:output => output_options,
:compress => compressor_options,
:mangle => mangle_options,
:parse => parse_options,
:sourceMap => source_map_options(input_map),
:ie8 => ie8?
}
parse_result(context.call("uglifier", options), generate_map, options)
end
def harmony?
@options[:harmony]
end
def harmony_error_message(message)
if message.start_with?("Unexpected token")
". To use ES6 syntax, harmony mode must be enabled with " \
"Uglifier.new(:harmony => true)."
else
""
end
end
def error_context_lines
@options.fetch(:error_context_lines, DEFAULTS[:error_context_lines]).to_i
end
def error_context_format_options(low, high, line_index, column)
line_width = high.to_s.size
{
:line_index => line_index,
:base_index => low,
:line_width => line_width,
:line_format => "\e[36m%#{line_width + 1}d\e[0m ", # cyan
:col => column
}
end
def format_error_line(line, options)
# light red
indicator = ' => '.rjust(options[:line_width] + 2)
colored_line = "#{line[0...options[:col]]}\e[91m#{line[options[:col]..-1]}"
"\e[91m#{indicator}\e[0m#{colored_line}\e[0m"
end
def format_lines(lines, options)
lines.map.with_index do |line, index|
if options[:base_index] + index == options[:line_index]
format_error_line(line, options)
else
"#{options[:line_format] % (options[:base_index] + index + 1)}#{line}"
end
end
end
def context_lines_message(source, line_number, column)
return if line_number.nil?
line_index = line_number - 1
lines = source.split("\n")
first_line = [line_index - error_context_lines, 0].max
last_line = [line_number + error_context_lines, lines.size].min
options = error_context_format_options(first_line, last_line, line_index, column)
context_lines = lines[first_line...last_line]
"--\n#{format_lines(context_lines, options).join("\n")}\n=="
end
def error_message(result, options)
err = result['error']
harmony_msg = harmony? ? '' : harmony_error_message(err['message'].to_s)
src_ctx = context_lines_message(options[:source], err['line'], err['col'])
"#{err['message']}#{harmony_msg}\n#{src_ctx}"
end
def parse_result(result, generate_map, options)
raise Error, error_message(result, options) if result.has_key?('error')
if generate_map
[result['code'] + source_map_comments, result['map']]
else
result['code'] + source_map_comments
end
end
def read_source(source)
if source.respond_to?(:read)
source.read
else
source.to_s
end
end
def mangle_options
defaults = conditional_option(
DEFAULTS[:mangle],
:keep_fnames => keep_fnames?(:mangle)
)
conditional_option(
@options[:mangle],
defaults,
:properties => mangle_properties_options
)
end
def mangle_properties_options
mangle_options = conditional_option(@options[:mangle], DEFAULTS[:mangle])
mangle_properties_options =
if @options.has_key?(:mangle_properties)
@options[:mangle_properties]
else
mangle_options && mangle_options[:properties]
end
options = conditional_option(mangle_properties_options, MANGLE_PROPERTIES_DEFAULTS)
if options && options[:regex]
options.merge(:regex => encode_regexp(options[:regex]))
else
options
end
end
def compressor_options
defaults = conditional_option(
DEFAULTS[:compress],
:global_defs => @options[:define] || {}
)
conditional_option(
@options[:compress],
defaults,
{ :keep_fnames => keep_fnames?(:compress) }.merge(negate_iife_block)
)
end
# Prevent negate_iife when wrap_iife is true
def negate_iife_block
if output_options[:wrap_iife]
{ :negate_iife => false }
else
{}
end
end
def comment_options
case comment_setting
when :all, true
true
when :jsdoc
"jsdoc"
when :copyright
encode_regexp(/(^!)|Copyright/i)
when Regexp
encode_regexp(comment_setting)
else
false
end
end
def quote_style
option = conditional_option(@options[:output], DEFAULTS[:output])[:quote_style]
case option
when :single
1
when :double
2
when :original
3
when Numeric
option
else # auto
0
end
end
def comment_setting
if @options.has_key?(:output) && @options[:output].has_key?(:comments)
@options[:output][:comments]
elsif @options.has_key?(:comments)
@options[:comments]
else
DEFAULTS[:output][:comments]
end
end
def output_options
migrate_braces(DEFAULTS[:output].merge(@options[:output] || {}))
.merge(:comments => comment_options, :quote_style => quote_style)
end
def migrate_braces(options)
if harmony?
options
else
options.merge(:braces => options[:bracketize]).delete_if { |key| key == :bracketize }
end
end
def ie8?
@options.fetch(:ie8, DEFAULTS[:ie8])
end
def keep_fnames?(type)
if @options[:keep_fnames] || DEFAULTS[:keep_fnames]
true
else
@options[type].respond_to?(:[]) && @options[type][:keep_fnames] ||
DEFAULTS[type].respond_to?(:[]) && DEFAULTS[type][:keep_fnames]
end
end
def source_map_options(input_map)
options = conditional_option(@options[:source_map], SOURCE_MAP_DEFAULTS) || SOURCE_MAP_DEFAULTS
{
:input => options[:filename],
:filename => options[:output_filename],
:root => options.fetch(:root) { input_map ? input_map["sourceRoot"] : nil },
:content => input_map,
#:map_url => options[:map_url],
:url => options[:url],
:includeSources => options[:sources_content]
}
end
def parse_options
conditional_option(@options[:parse], DEFAULTS[:parse])
.merge(parse_source_map_options)
end
def parse_source_map_options
if @options[:source_map].respond_to?(:[])
{ :filename => @options[:source_map][:filename] }
else
{}
end
end
def enclose_options
if @options[:enclose]
@options[:enclose].map do |pair|
pair.first + ':' + pair.last
end
else
false
end
end
def encode_regexp(regexp)
modifiers = if regexp.casefold?
"i"
else
""
end
[regexp.source, modifiers]
end
def conditional_option(value, defaults, overrides = {})
if value == true || value.nil?
defaults.merge(overrides)
elsif value
defaults.merge(value).merge(overrides)
else
false
end
end
def sanitize_map_root(map)
if map.nil?
nil
elsif map.is_a? String
sanitize_map_root(JSON.parse(map))
elsif map["sourceRoot"] == ""
map.merge("sourceRoot" => nil)
else
map
end
end
def extract_source_mapping_url(source)
comment_start = %r{(?://|/\*\s*)}
comment_end = %r{\s*(?:\r?\n?\*/|$)?}
source_mapping_regex = /#{comment_start}[@#]\ssourceMappingURL=\s*(\S*?)#{comment_end}/
rest = /\s#{comment_start}[@#]\s[a-zA-Z]+=\s*(?:\S*?)#{comment_end}/
regex = /#{source_mapping_regex}(?:#{rest})*\Z/m
match = regex.match(source)
match && match[1]
end
def input_source_map(source, generate_map)
return nil unless generate_map
source_map_options = @options[:source_map].is_a?(Hash) ? @options[:source_map] : {}
sanitize_map_root(source_map_options.fetch(:input_source_map) do
url = extract_source_mapping_url(source)
url.split(",", 2)[-1].unpack1('m0') if url && url.start_with?("data:")
end)
rescue ArgumentError, JSON::ParserError
nil
end
end