title: Vuejs App works in dev breaks in production -- build errors
body: <p>My Vuejs app runs successfully in dev localhost but once I run the build command I get these difficult-to-debug errors. I deployed it successfully last week. </p>
  
  <p>I'm assuming its my package.json file not containing the right dependencies so I copied that file from the successful build, deleted my node_modules folder and reinstalled -- no go.</p>
  
  <h1>My Package.json</h1>
  
  <pre><code>{
    "name": "client",
    "version": "1.0.0",
    "description": "A Vue.js project",
    "author": "-----------------",
    "private": true,
    "scripts": {
      "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
      "start": "npm run dev",
      "lint": "eslint --ext .js,.vue src",
      "build": "node build/build.js"
    },
    "dependencies": {
      "@fortawesome/fontawesome-svg-core": "^1.2.19",
      "@fortawesome/free-brands-svg-icons": "^5.9.0",
      "@fortawesome/free-solid-svg-icons": "^5.9.0",
      "@fortawesome/vue-fontawesome": "^0.1.6",
      "axios": "^0.18.0",
      "eslint-plugin-vue": "^5.2.2",
      "tiptap": "^1.14.0",
      "tiptap-extensions": "^1.14.0",
      "vue": "^2.5.2",
      "vue-headful": "^2.0.1",
      "vue-infinite-scroll": "^2.0.2",
      "vue-router": "^3.0.1",
      "vuetify": "^1.5.1",
      "vuex": "^3.1.0",
      "vuex-router-sync": "^5.0.0"
    },
    "devDependencies": {
      "autoprefixer": "^7.1.2",
      "babel-core": "^6.22.1",
      "babel-eslint": "^8.2.1",
      "babel-helper-vue-jsx-merge-props": "^2.0.3",
      "babel-loader": "^7.1.1",
      "babel-plugin-syntax-jsx": "^6.18.0",
      "babel-plugin-transform-runtime": "^6.22.0",
      "babel-plugin-transform-vue-jsx": "^3.5.0",
      "babel-preset-env": "^1.3.2",
      "babel-preset-stage-2": "^6.22.0",
      "chalk": "^2.0.1",
      "copy-webpack-plugin": "^4.0.1",
      "css-loader": "^0.28.0",
      "eslint": "^4.15.0",
      "eslint-config-standard": "^10.2.1",
      "eslint-friendly-formatter": "^3.0.0",
      "eslint-loader": "^1.7.1",
      "eslint-plugin-import": "^2.7.0",
      "eslint-plugin-node": "^5.2.0",
      "eslint-plugin-promise": "^3.4.0",
      "eslint-plugin-standard": "^3.0.1",
      "extract-text-webpack-plugin": "^3.0.0",
      "file-loader": "^1.1.4",
      "friendly-errors-webpack-plugin": "^1.6.1",
      "html-webpack-plugin": "^2.30.1",
      "material-design-icons-iconfont": "^4.0.4",
      "node-notifier": "^5.1.2",
      "node-sass": "^4.11.0",
      "optimize-css-assets-webpack-plugin": "^3.2.0",
      "ora": "^1.2.0",
      "portfinder": "^1.0.13",
      "postcss-import": "^11.0.0",
      "postcss-loader": "^2.0.8",
      "postcss-url": "^7.2.1",
      "rimraf": "^2.6.0",
      "sass-loader": "^7.1.0",
      "semver": "^5.3.0",
      "shelljs": "^0.7.6",
      "uglifyjs-webpack-plugin": "^1.1.1",
      "url-loader": "^1.1.2",
      "vue-loader": "^13.3.0",
      "vue-style-loader": "^3.0.1",
      "vue-svg-loader": "^0.12.0",
      "vue-template-compiler": "^2.5.2",
      "webpack": "^3.12.0",
      "webpack-bundle-analyzer": "^2.9.0",
      "webpack-cli": "^3.2.3",
      "webpack-dev-server": "^2.9.7",
      "webpack-merge": "^4.1.0"
    },
    "engines": {
      "node": "&gt;= 6.0.0",
      "npm": "&gt;= 3.0.0"
    },
    "browserslist": [
      "&gt; 1%",
      "last 2 versions",
      "not ie &lt;= 8"
    ]
  }
  </code></pre>
  
  <h1>The error message</h1>
  
  <pre><code> building for production...Error processing file: static/css/app.61609d17f4630a9d62a16c4312c20c20.css
  (node:23459) UnhandledPromiseRejectionWarning: CssSyntaxError: /Users/jon/Documents/Personal Projects/tmp/blog-site/client/static/css/app.61609d17f4630a9d62a16c4312c20c20.css:536:5: Unknown word
      at Input.error (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/input.js:130:16)
      at Parser.unknownWord (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/parser.js:563:22)
      at Parser.decl (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/parser.js:235:16)
      at Parser.other (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/parser.js:133:18)
      at Parser.parse (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/parser.js:77:16)
      at parse (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/parse.js:17:12)
      at new LazyResult (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/lazy-result.js:60:16)
      at Processor.&lt;anonymous&gt; (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/processor.js:138:12)
      at Processor.process (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/processor.js:117:23)
      at Function.creator.process (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/node_modules/postcss/lib/postcss.js:148:43)
      at OptimizeCssAssetsPlugin.processCss (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/index.js:63:19)
      at Object.processor (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/optimize-css-assets-webpack-plugin/index.js:29:23)
      at /Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/last-call-webpack-plugin/index.js:139:8
      at arrayEach (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/lodash/_arrayEach.js:15:9)
      at forEach (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/lodash/forEach.js:38:10)
      at LastCallWebpackPlugin.process (/Users/jon/Documents/Personal Projects/tmp/blog-site/client/node_modules/last-call-webpack-plugin/index.js:136:3)
  (node:23459) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
  (node:23459) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
  </code></pre>