title: Minify / Optimize NextJS site
body: <p>I have a nextjs site.</p>
  
  <p>My common.js and my custom.scss don't be minified by next.</p>
  
  <p>I tried the next one in next.config.js:</p>
  
  <pre><code>const withSass = require('@zeit/next-sass')
  const withOptimizedImages = require('next-optimized-images');
  const withTypescript = require('@zeit/next-typescript')
  module.exports = withSass({minified:true},withOptimizedImages(withTypescript()))
  </code></pre>
  
  <p>My .babelrc</p>
  
  <pre><code>{
      "presets": [
          "next/babel",
          "@zeit/next-typescript/babel",
          "minify"
      ]
  }
  </code></pre>
  
  <p>My tsconfig.json</p>
  
  <pre><code>{
      "compilerOptions": {
          "allowJs": true,
          "allowSyntheticDefaultImports": true,
          "jsx": "preserve",
          "lib": [
              "dom",
              "es2017"
          ],
          "module": "esnext",
          "moduleResolution": "node",
          "noEmit": true,
          "noUnusedLocals": true,
          "noUnusedParameters": true,
          "preserveConstEnums": true,
          "removeComments": true,
          "skipLibCheck": true,
          "sourceMap": true,
          "strict": true,
          "target": "esnext"
      }
  }
  </code></pre>
  
  <p>It should work or i have to implement some thing more?</p>