Uglifier Cannot Precompile JS Optional Chaining

[kduraiswami]

Hi There

I am trying to precompile assets with config.assets.js_compressor = Uglifier.new(harmony: true) and I receive the error Uglifier::Error: Unexpected token: punc (.) for JS syntax like this: .data('id'))?.advanced_settings

Full Stacktrace:

/mypath/app/assets/config/manifest.js:2 /usr/local/rvm/gems/ruby-2.5.1/gems/uglifier-4.2.0/lib/uglifier.rb:291:in parse_result' /usr/local/rvm/gems/ruby-2.5.1/gems/uglifier-4.2.0/lib/uglifier.rb:221:in run_uglifyjs' /usr/local/rvm/gems/ruby-2.5.1/gems/uglifier-4.2.0/lib/uglifier.rb:166:in compile' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/compressing.rb:65:in block in js_compressor=' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/legacy_proc_processor.rb:31:in call' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:75:in call_processor' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:57:in block in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in reverse_each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:134:in load_from_unloaded' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:60:in block in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:317:in fetch_asset_from_dependency_cache' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:44:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:20:in block in initialize' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:47:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:388:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:357:in block in link_paths' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:367:in block in resolve_paths' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:363:in each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:363:in resolve_paths' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:356:in link_paths' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:317:in process_link_directory_directive' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:180:in block in process_directives' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:178:in each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:178:in process_directives' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:83:in _call' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/directive_processor.rb:68:in call' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:75:in call_processor' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:57:in block in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in reverse_each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:134:in load_from_unloaded' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:60:in block in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:317:in fetch_asset_from_dependency_cache' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:44:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:20:in block in initialize' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:47:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/bundle.rb:23:in block in call' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/utils.rb:200:in dfs' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/bundle.rb:24:in call' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:75:in call_processor' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:57:in block in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in reverse_each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/processor_utils.rb:56:in call_processors' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:134:in load_from_unloaded' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:60:in block in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:317:in fetch_asset_from_dependency_cache' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/loader.rb:44:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:20:in block in initialize' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/cached_environment.rb:47:in load' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/base.rb:66:in find_asset' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/base.rb:73:in find_all_linked_assets' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:134:in block in find' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:133:in each' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:133:in find' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/sprockets/manifest.rb:186:in compile' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-rails-3.2.1/lib/sprockets/rails/task.rb:68:in block (3 levels) in define' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-3.7.2/lib/rake/sprocketstask.rb:147:in with_logger' /usr/local/rvm/gems/ruby-2.5.1/gems/sprockets-rails-3.2.1/lib/sprockets/rails/task.rb:67:in block (2 levels) in define' /usr/local/rvm/gems/ruby-2.5.1/gems/rake-13.0.1/exe/rake:27:in <top (required)>' /usr/local/rvm/gems/ruby-2.5.1/bin/ruby_executable_hooks:24:in eval' /usr/local/rvm/gems/ruby-2.5.1/bin/ruby_executable_hooks:24:in

' Tasks: TOP => assets:precompile Let me know if I can provide any additional context or if this has already been fixed elsewhere.

[sylwesternourish]

I am having the same issue when using Uglifier on Rails 5.2.3, is there any work around apart from disabling Uglifier?

[cs0511]

Same issue

[mike-usa]

The Safe Navigation / Optional Chaining operator (?.) was first introduced in ECMAScript 2020 (ES2020). For various reasons, Uglifier supports up to ES5 (ES6 with harmony: true). #43610 leads to (https://github.com/rails/sprockets/pull/713), which mentions to use terser gem instead.

Add terser to the Gemfile

bundle install terser

Add it to your configuration files where you want to compress (e.g., config/production.rb):

config.assets.js_compressor = :terser