title: Can't resolve module (not found) in React.js
body: <p>I can't believe that I'm asking an obvious question, but I still get the error in console log.</p>
  
  <p>Console says that it can't find the module in the directory, but I've checked at least 10 times for typos. Anyways, here's the component code.</p>
  
  <p>I want to render <strong>Header</strong> in root</p>
  
  <pre><code>import React, { Component } from 'react'
  import Header from './src/components/header/header'
  import logo from './logo.svg'
  import './App.css'
  
  class App extends Component {
    render() {
      return (
        &lt;Header/&gt;
      );
    }
  }
  
  export default App;
  </code></pre>
  
  <p>This is the <code>Header</code> component</p>
  
  <pre><code>import React, { Component } from 'react'
  import ReactDOM from 'react-dom'
  import navBar from './src/components/header/navBar'
  import './src/css/header.css'
  
  class Header extends Component {
      render() {
          return {
              &lt;div&gt;
               &lt;div id="particles-js"&gt;&lt;/div&gt;
               &lt;navBar/&gt;
               &lt;Title/&gt;
            &lt;/div&gt;
          };
      }
  }
  
  ReactDOM.render(&lt;Header/&gt;, document.getElementById('header'));
  </code></pre>
  
  <p>I've checked at least 10 times that the module is at this location <code>./src/components/header/header</code>, and it is (folder "header" contains "header.js").</p>
  
  <p>Yet, React still throws this error:</p>
  
  <p><strong>Failed to compile</strong></p>
  
  <p><code>./src/App.js
  Module not found: Can't resolve './src/components/header/header' in '/home/wiseman/Desktop/React_Components/github-portfolio/src'</code></p>
  
  <p><strong>npm test</strong> says the same thing. </p>