部署到 Heroku：ExecJS::RuntimeError: SyntaxError: Unexpected token

Question

我在 Stackoverflow 中看到了类似的 post 并出现了类似的错误，但据我所知，它没有得到解决，而且似乎与我的问题之间存在一些差异。

一切（当然）在本地完美运行。但是，当推送到 Heroku 时，我会感到很疯狂：

remote: -----> Detecting rake tasks
remote: -----> Preparing app for Rails asset pipeline
remote:        Running: rake assets:precompile
remote:        rake aborted!
remote:        ExecJS::RuntimeError: SyntaxError: Unexpected token punc «{», expected punc «(»
remote:        JS_Parse_Error.Object.defineProperty.get ((execjs):3538:621)
remote:        (execjs):4060:47
remote:        (execjs):1:102
remote:        Object.<anonymous> ((execjs):1:120)
remote:        Module._compile (module.js:456:26)
remote:        Object.Module._extensions..js (module.js:474:10)
remote:        Module.load (module.js:356:32)
remote:        Function.Module._load (module.js:312:12)
remote:        Function.Module.runMain (module.js:497:10)
remote:        startup (node.js:119:16)
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/execjs-2.7.0/lib/execjs/external_runtime.rb:39:in `exec'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/execjs-2.7.0/lib/execjs/external_runtime.rb:21:in `eval'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/execjs-2.7.0/lib/execjs/external_runtime.rb:46:in `call'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/uglifier-3.1.6/lib/uglifier.rb:190:in `run_uglifyjs'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/uglifier-3.1.6/lib/uglifier.rb:152:in `compile'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/uglifier_compressor.rb:53:in `call'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/uglifier_compressor.rb:28:in `call'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/processor_utils.rb:75:in `call_processor'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/processor_utils.rb:57:in `block in call_processors'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/processor_utils.rb:56:in `reverse_each'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/processor_utils.rb:56:in `call_processors'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/loader.rb:134:in `load_from_unloaded'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/loader.rb:60:in `block in load'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/loader.rb:317:in `fetch_asset_from_dependency_cache'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/loader.rb:44:in `load'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/cached_environment.rb:20:in `block in initialize'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/cached_environment.rb:47:in `yield'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/cached_environment.rb:47:in `load'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/base.rb:66:in `find_asset'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/base.rb:73:in `find_all_linked_assets'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/manifest.rb:142:in `block in find'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/legacy.rb:114:in `block (2 levels) in logical_paths'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/path_utils.rb:228:in `block in stat_tree'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/path_utils.rb:212:in `block in stat_directory'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/path_utils.rb:209:in `each'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/path_utils.rb:209:in `stat_directory'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/path_utils.rb:227:in `stat_tree'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/legacy.rb:105:in `each'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/legacy.rb:105:in `block in logical_paths'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/legacy.rb:104:in `each'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/legacy.rb:104:in `logical_paths'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/manifest.rb:140:in `find'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/sprockets/manifest.rb:185:in `compile'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-3.2.0/lib/sprockets/rails/task.rb:68:in `block (3 levels) in define'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-3.7.1/lib/rake/sprocketstask.rb:147:in `with_logger'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-3.2.0/lib/sprockets/rails/task.rb:67:in `block (2 levels) in define'
remote:        /tmp/build_c7ded3066a4d98b445e04f25befe0b17/vendor/bundle/ruby/2.2.0/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
remote:        Tasks: TOP => assets:precompile
remote:        (See full trace by running task with --trace)
remote:  !
remote:  !     Precompiling assets failed.
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote: 
remote:  !     Push failed

而且它一直在继续。我不认识这里的任何东西。我的项目非常基础——它还没有自定义 .js 文件或任何东西。本质上，它是一个具有静态页面控制器的 Rails 应用程序。我什至不知道从哪里开始寻找问题。在类似的post 上，有人提到他们删除了 uglifier gem。这根本没有改变我的结果。

感谢您提出任何建议，但请理解我实际上一无所知：我需要基本的分步说明，就好像我是 4 岁的孩子一样。此外，我确实有一个因挫折而产生的愚蠢问题：为什么它没有给我一个错误，该错误实际上指向 I 生成的代码中的特定内容，而不是所有这些看似自动生成的垃圾?

提前致谢。

宝石文件：

source 'https://rubygems.org'

git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end


gem 'rails', '~> 5.0.1'
gem 'bcrypt',         '3.1.11'
gem 'faker',          '1.6.6'
gem 'carrierwave', '~> 1.0'
gem 'mini_magick'
gem 'fog'
gem 'will_paginate',           '3.1.0'
gem 'bootstrap-will_paginate', '0.0.10'
gem 'bootstrap-sass', '3.3.6'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.2'
gem 'jquery-rails'
gem 'turbolinks', '~> 5'
gem 'jbuilder', '~> 2.5'
gem 'puma'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'sqlite3'
  gem 'byebug', platform: :mri
end

group :development do
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '~> 3.0.5'
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

group :test do
  gem 'rails-controller-testing', '0.1.1'
  gem 'minitest-reporters',       '1.1.9'
  gem 'guard',                    '2.13.0'
  gem 'guard-minitest',           '2.4.4'
end

group :production do
  gem 'pg'
  gem 'rails_12factor', '0.0.2'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

application.js：

// This is a manifest file that'll be compiled into application.js, which will include all the files
// listed below.
//
// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
// or any plugin's vendor/assets/javascripts directory can be referenced here using a relative path.
//
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// compiled file. JavaScript code in this file should be added after the last require_* statement.
//
// Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
// about supported directives.
//
//= require jquery
//= require jquery_ujs
//= require turbolinks
//= require_tree .

Answer 1

最终为我解决了这个问题（至少这次）是：

1. 在本地预编译资产（rake assets:precompile）。这在本地系统上创建了两个文件 - 认为它们是 gz 文件）。
2. 提交并推送到 Heroku。在此之后它起作用了。

虽然，这对我没有任何解释。我以前从来不需要预编译资产。而且，如果有必要这样做，为什么 localhost 总是在不执行此命令的情况下工作？而且，Heroku 总是尝试预编译资产。为什么当我推送所谓的预编译资产时它会成功？反正不重做预编译吗？

所以，现在，问题解决了。我不知道为什么。