Build a React sidebar navigation component
Tags: react, tutorial, webdev, javascript
Published: 2020-09-09 05:02:54

In this tutorial we’ll be building a slide-out sidebar navigation component. Traditionally this type of navigation was implemented on mobile devices but it’s becoming common practice to use them on desktop devices.

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/i/ic25ayk3l13hfxajy80k.gif)

We’ll be creating pages for each of the links in the navigation so you’ll also get an introduction to [React Router](https://reactrouter.com/) if you haven’t already.

Let’s get started by setting up the project using the React Create App package:

```
npx react-create-app react-sidebar
```

The only dependency required is React Router so let’s install that as well:

```
npm install react-router-dom
```

Create a `pages` folder in the `src` directory with `home.js`, `services.js`, and `contact.js` files. These are just placeholder files so we can navigate between the pages in our navigation. 

Inside each of the files we’ll render some simple content so we can see when the page has changed. Be sure to replace the function name and text in each file to correspond with the filename:

```javascript
import React from "react";

function Home() {
  return (
    <div className="page">
      <h1>Home</h1>
      <p>This is the home page.</p>
    </div>
  );
}

export default Home;
```

Next create a `components` folder in the `src` directory with a `Sidebar.js` and `Sidebar.css` file:

Inside `Sidebar.js` add the following imports:

```javascript
import React, { useState } from "react";
import { Link } from "react-router-dom";
import "./Sidebar.css";
useState hook will be used to store the “active” state of the navigation and Link is used to render the links.
```

Next add a `Sidebar()` function as follows:

```javascript
function Sidebar() {
  const [sidebar, setSidebar] = useState(false);
  const showSidebar = () => setSidebar(!sidebar);
  return (
    <nav className={sidebar ? "sidebar active" : "sidebar"}>
      <button className="hamburger" type="button" onClick={showSidebar}>
        <div></div>
      </button>
      <ul onClick={showSidebar}>
        <li><Link to="/">Home</Link></li>
        <li><Link to="/services">Services</Link></li>
        <li><Link to="/contact">Contact</Link></li>
      </ul>
    </nav>
  );
}
export default Sidebar;
```

When the `onClick` is triggered we set the sidebar state to true which adds an `active` class. You’ll see later when CSS is applied that the `active` class shifts the position of the sidebar from offscreen to the left edge. 

`<Link>` renders a fully accessible anchor tag which contains the URL that we'll route to the corresponding file in the pages folder.

With the sidebar component completed when can now load it into `App.js` and setup the routes, but first the imports:

```javascript
import React from "react";
import { BrowserRouter as Router, Switch, Route } from "react-router-dom";
import Home from "./pages/Home";
import Services from "./pages/Services";
import Contact from "./pages/Contact";
import Sidebar from "./components/Sidebar";
import "./App.css";
```

Then edit the `App()` function as follows:

```javascript
function App() {
  return (
    <>
      <Router>
        <Sidebar />
        <Switch>
          <Route path="/" exact component={Home} />
          <Route path="/services" component={Services} />
          <Route path="/contact" component={Contact} />
        </Switch>
      </Router>
    </>
  );
}

export default App;
```

`<Router>` is the primary component of React Router that’s responsible for keeping the UI and the URL in sync. <Switch> looks through all its children <Route> elements and renders the first one with a path matching the current URL.

That’s it for the JavaScript we can now add some CSS inside `Sidebar.css`.

First we’ll set the default position of the sidebar off-screen. Then when the active class is triggered it’s position changes to align on the left side of the browser. As the sidebar has a `transition` it’ll animate into position.

```css
.sidebar {
  position: fixed;
  top: 0;
  left: -300px;
  width: 300px;
  height: 100%;
  background-color: peru;
  transition: left 300ms ease-out;
}
.sidebar.active {
  left: 0;
}
```

Next some basic style for each of the links in the navigation:

```css
.sidebar ul {
  margin: 0;
  padding: 0;
}
.sidebar li {
  list-style: none;
}
.sidebar li a {
  font-size: 18px;
  text-decoration: none;
  padding: 10px;
  display: block;
  color: #fff;
}
```

A hamburger (menu) icon can be created with CSS:

```css
.hamburger {
  border: none;
  outline: 0;
  width: 50px;
  position: absolute;
  right: -50px;
  background-color: peru;
}

.hamburger:after,
.hamburger:before,
.hamburger div {
  background-color: #fff;
  height: 5px;
  margin: 7px 0;
  border-radius: 3px;
  content: "";
  display: block;
  transition: all 300ms ease-in-out;
}
```

Finally we can transform the hamburger icon into a cross icon when the sidebar is active:

```css
.sidebar.active .hamburger:before {
  transform: translateY(12px) rotate(135deg);
}
.sidebar.active .hamburger::after {
  transform: translateY(-12px) rotate(-135deg);
}
.sidebar.active .hamburger div {
  transform: scale(0);
}
```

This CSS hides the middle row of the hamburger icon and rotates the top (`:before`) and bottom (`:after`) rows to form a cross.