title: Webpacker::Manifest::MissingEntryError in App#index
body: <p>I've been trying to setup my dev environment using Rails v.  6.0.2.1 with webpacker creating a server on port 3035 while having a PostgreSQL database running on 5432. This is all done on windows, btw.</p>
  <p>Essentially, I've been running into the issue that whenever I managed to get a steady connection to the database, webpacker appears to fail the compiling of my code and only produces a MissingEntryError. I've previously been able to produce a Manifest.Json file in my public/packs, but it was to my understanding that this file is autogenerated by the plugin.</p>
  <p>Any idea what I could be doing wrong?</p>
  <p>webpacker.yml</p>
  <pre><code># Note: You must restart bin/webpack-dev-server for changes to take effect
  
  default: &amp;default
    source_path: app/javascript
    source_entry_path: packs
    public_root_path: public
    public_output_path: packs
    cache_path: tmp/cache/webpacker
    check_yarn_integrity: false
    webpack_compile_output: true
  
    # Additional paths webpack should lookup modules
    # ['app/assets', 'engine/foo/app/assets']
    resolved_paths: []
  
    # Reload manifest.json on all requests so we reload latest compiled packs
    cache_manifest: false
  
    # Extract and emit a css file
    extract_css: false
  
    static_assets_extensions:
      - .jpg
      - .jpeg
      - .png
      - .gif
      - .tiff
      - .ico
      - .svg
      - .eot
      - .otf
      - .ttf
      - .woff
      - .woff2
  
    extensions:
      - .mjs
      - .js
      - .jsx
      - .sass
      - .scss
      - .css
      - .module.sass
      - .module.scss
      - .module.css
      - .png
      - .svg
      - .gif
      - .jpeg
      - .jpg
  
  development:
    &lt;&lt;: *default
    compile: true
  
    # Verifies that correct packages and versions are installed by inspecting package.json, yarn.lock, and node_modules
    check_yarn_integrity: true
  
    # Reference: https://webpack.js.org/configuration/dev-server/
    dev_server:
      https: false
      host: localhost
      port: 3035
      public: localhost:3035
      hmr: false
      # Inline should be set to true if using HMR
      inline: true
      overlay: true
      compress: true
      disable_host_check: true
      use_local_ip: false
      quiet: false
      pretty: false
      headers:
        'Access-Control-Allow-Origin': '*'
      watch_options:
        ignored: '**/node_modules/**'
  
  
  test:
    &lt;&lt;: *default
    compile: true
  
    # Compile test packs to a separate directory
    public_output_path: packs-test
  
  production:
    &lt;&lt;: *default
  
    # Production depends on precompilation of packs prior to booting for performance.
    compile: false
  
    # Extract and emit a css file
    extract_css: true
  
    # Cache manifest.json for performance
    cache_manifest: true
  </code></pre>
  <p>And this is the webpacker error log</p>
  <pre><code>ActionView::Template::Error (Webpacker can't find application in C:/Users/Bruger/Desktop/hydac-rails/public/packs/manifest.json. Possible causes:
  1. You want to set webpacker.yml value of compile to true for your environment
     unless you are using the `webpack -w` or the webpack-dev-server.
  2. webpack has not yet re-run to reflect updates.
  3. You have misconfigured Webpacker's config/webpacker.yml file.
  4. Your webpack configuration is not creating a manifest.
  Your manifest contains:
  {
  }
  ):
      18:
      19:     &lt;%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' %&gt;
      20:     &lt;%= stylesheet_pack_tag &quot;application&quot;, media: &quot;all&quot;, &quot;data-turbolinks-track&quot;: &quot;reload&quot; %&gt;
      21:     &lt;%= javascript_pack_tag 'application', 'data-turbolinks-track': 'reload' %&gt;
      22:     &lt;%= javascript_pack_tag 'app' %&gt;
      23:     &lt;%= stylesheet_pack_tag 'app' %&gt;
      24:     &lt;link href=&quot;https://fonts.googleapis.com/css?family=Heebo|Lato:400,700&amp;display=swap&quot; rel=&quot;stylesheet&quot;&gt;
  
  app/views/layouts/application.html.erb:21
  
  </code></pre>
  <p>Based on question from @stwienert</p>
  <p>contents of webpack</p>
  <pre><code>#!/usr/bin/env ruby
  
  ENV[&quot;RAILS_ENV&quot;] ||= ENV[&quot;RACK_ENV&quot;] || &quot;development&quot;
  ENV[&quot;NODE_ENV&quot;]  ||= &quot;development&quot;
  
  require &quot;pathname&quot;
  ENV[&quot;BUNDLE_GEMFILE&quot;] ||= File.expand_path(&quot;../../Gemfile&quot;,
    Pathname.new(__FILE__).realpath)
  
  require &quot;bundler/setup&quot;
  
  require &quot;webpacker&quot;
  require &quot;webpacker/webpack_runner&quot;
  
  APP_ROOT = File.expand_path(&quot;..&quot;, __dir__)
  Dir.chdir(APP_ROOT) do
    Webpacker::WebpackRunner.run(ARGV)
  end
  </code></pre>
  <p>Output of npx run webpack</p>
  <pre><code>C:\Users\Bruger\Desktop\hydac-rails\bin\webpack:3
  ENV[&quot;RAILS_ENV&quot;] ||= ENV[&quot;RACK_ENV&quot;] || &quot;development&quot;
                   ^^^
  
  SyntaxError: Unexpected token '||='
      at wrapSafe (internal/modules/cjs/loader.js:979:16)
      at Module._compile (internal/modules/cjs/loader.js:1027:27)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
      at Module.load (internal/modules/cjs/loader.js:928:32)
      at Function.Module._load (internal/modules/cjs/loader.js:769:14)
      at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
      at internal/main/run_main_module.js:17:47
  
  </code></pre>
  <p>And a picture of my javascript/packs folder
  <a href="https://i.stack.imgur.com/XVx82.png" rel="nofollow noreferrer">javascript/packs folder</a></p>