部署Rails应用至Heroku时遭遇Uglifier正则表达式无效字符错误

Hey there, let's tackle this Uglifier regex error you're hitting on Heroku. I've seen this pop up a few times when deploying from Windows to Heroku, so here's what you can try to get your app up and running:

• Hunt down problematic regex in your JavaScript files
  Uglifier (which relies on UglifyJS) is stricter than most browsers when it comes to regex syntax. Dig through all your .js and .js.erb files for regex patterns that might have invalid characters—like unescaped backslashes, or Unicode property escapes (e.g., /\p{L}/) that older UglifyJS versions don't support. Adjust those regexes to use compatible syntax.

• Update your Uglifier gem
  Older versions of Uglifier often have trouble with modern JS syntax. Open your Gemfile and set a recent version of the gem:

  gem 'uglifier', '>= 4.2.0'
  

  Run bundle update uglifier locally to lock in the new version (even though Heroku will rebuild dependencies, this ensures you're starting with a compatible base).

• Enable ES6 support for Uglifier
  If your JavaScript uses ES6+ features, Uglifier might need a little extra configuration to handle them. Add this line to your config/environments/production.rb:

  config.assets.js_compressor = Uglifier.new(harmony: true)
  

  The harmony flag lets Uglifier process ES6 syntax without throwing errors.

• Test asset precompile locally first
  Save yourself the hassle of deploying to Heroku repeatedly by replicating the error locally. In production mode, run:

  # For Command Prompt on Windows
  set RAILS_ENV=production
  bundle exec rake assets:precompile
  
  # For PowerShell
  $env:RAILS_ENV="production"
  bundle exec rake assets:precompile
  

  This will tell you exactly which file is causing the regex issue, so you can fix it directly without guessing.

• Check your JS file encodings
  Windows sometimes saves files with non-UTF-8 encodings (like UTF-16 with BOM) that cause problems on Linux-based Heroku. Open your JS files in a code editor (like VS Code) and confirm they're saved as UTF-8 without BOM—you can check and change this via the encoding dropdown in the bottom-right corner of the editor.

• Tweak your Heroku buildpacks
  Your deployment log shows both Ruby and Node.js buildpacks were detected. If you have Node dependencies (like yarn or webpack), make sure the Node buildpack runs first to install necessary tools. Set the buildpack order with these commands:

  heroku buildpacks:set heroku/ruby
  heroku buildpacks:add --index 1 heroku/nodejs
  

内容的提问来源于stack exchange，提问作者Nijeesh K J