title: After upgrading to Snowpack 3 cannot find files
body: <p>I'm using Snowpack + Svelte. After upgrading to Snowpack 3 is not working anymore and I can't configure <code>mount</code> in <code>snowpack.config.js</code> properly.</p>
  <p>Don't understand exactly why it cannot find <code>App.js</code> also it's trying to find <code>.jsx</code>, <code>.ts</code>...</p>
  <pre class="lang-sh prettyprint-override"><code>[404] /_dist_/screens/App.js
  </code></pre>
  <p><strong>index.html</strong></p>
  <pre class="lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html lang=&quot;en&quot;&gt;
  &lt;head&gt;
      &lt;meta charset=&quot;utf-8&quot;&gt;
      &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width,initial-scale=1&quot;&gt;
      &lt;link rel=&quot;stylesheet&quot; href=&quot;global.css&quot;&gt;
      &lt;script type=&quot;module&quot; defer src=&quot;_dist_/main.js&quot;&gt;&lt;/script&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  <p>And then in my <strong>snowpack.config.js</strong></p>
  <pre class="lang-js prettyprint-override"><code>/** @type {import(&quot;snowpack&quot;).SnowpackUserConfig } */
  module.exports = {
    mount: {
      public: '/',
      src: '/_dist_',
    },
    plugins: [
      '@snowpack/plugin-svelte',
      '@snowpack/plugin-dotenv',
    ],
    routes: [
      /* Enable an SPA Fallback in development: */
      // {&quot;match&quot;: &quot;routes&quot;, &quot;src&quot;: &quot;.*&quot;, &quot;dest&quot;: &quot;/index.html&quot;},
    ],
    optimize: {
      /* Example: Bundle your final build: */
      // &quot;bundle&quot;: true,
    },
    packageOptions: {
      /* ... */
    },
    devOptions: {
      /* ... */
    },
    buildOptions: {
      /* ... */
    },
    alias: {
      components: './src/components',
      screens: './src/screens',
      lib: './src/lib'
    },
  };
  </code></pre>
  <p>I also tried:</p>
  <pre class="lang-js prettyprint-override"><code>  mount: {
      // Same behavior as the &quot;src&quot; example above:
      &quot;src&quot;: {url: &quot;/dist&quot;},
      // Mount &quot;public&quot; to the root URL path (&quot;/*&quot;) and serve files with zero transformations:
      &quot;public&quot;: {url: &quot;/&quot;, static: true, resolve: false}
    },
  </code></pre>
  <p>So now it's complaining less but still not working</p>
  <pre class="lang-sh prettyprint-override"><code>[snowpack] [404] /_dist_/main.js
  
  </code></pre>
  <p><strong>Files structure</strong></p>
  <pre class="lang-sh prettyprint-override"><code>root
  --node-modules
  --public
  ----global.css
  ----index.html
  --src
  ----components
  ----lib
  ----screens
  ----main.js
  --snowpack.config.js
  ...
  </code></pre>
  <p><strong>package.json</strong></p>
  <pre class="lang-json prettyprint-override"><code>  &quot;devDependencies&quot;: {
      &quot;@snowpack/plugin-dotenv&quot;: &quot;^2.0.5&quot;,
      &quot;@snowpack/plugin-svelte&quot;: &quot;^3.5.0&quot;,
      &quot;@snowpack/web-test-runner-plugin&quot;: &quot;^0.2.1&quot;,
      &quot;@testing-library/svelte&quot;: &quot;^3.0.3&quot;,
      &quot;@web/test-runner&quot;: &quot;^0.12.2&quot;,
      &quot;chai&quot;: &quot;^4.2.0&quot;,
      &quot;smart-webcomponents&quot;: &quot;^9.0.0&quot;,
      &quot;snowpack&quot;: &quot;^3.0.10&quot;,
      &quot;svelte&quot;: &quot;^3.31.2&quot;,
      &quot;svelte-i18n&quot;: &quot;^3.3.0&quot;
    }
  </code></pre>
  <p>Any help or idea will be really appreciated.</p>