React Components Lab

Overview

In this lab, you'll write React components and render them into the DOM.

Note: there is already a bit of code in index.js. Don't remove it: you'll need it to complete the exercise!

First Things First

Make sure to import React and ReactDOM into your /src/index.js file. For now, we will program all of our React components in this one file.

As mentioned above, there is some starter code in this file to mount the components. In addition, there are three classes in this file that are extending the React.Component class. These will be our components! In this lab, will be writing all of our components using the ES6 class syntax: class YourComponent extends React.Component {}

If the export keyword on our components raised an eyebrow, with you thinking: "If we are going to use the classes in the same file they are defined in, why do we need to export them?", then you are spot on! The reason we are exporting them here is so that our testing suite will have access to them.

Deliverables

The Oldercoaster

In index.js, implement your OlderCoaster. It should render the following HTML:

<div class="oldercoaster">
  <p>Two grannies having the time of their life!</p>
  <p>Passengers:</p>
  <ul>
    <li>Agnes</li>
    <li>Muriel</li>
  </ul>
</div>

Don't look too far

In index.js, create another React component called InFrontOfYou. It should render the following HTML:

<div>
  <p>You shouldn't look too far.</p>
  <p>Sometimes, the solution is right in front of you.</p>
</div>

Ye Olde Meat Shoppe

In index.js, create one more React component called ButcherShop. It should render the following HTML:

<div class="butcher-shop">
  <p>Hello! We have the following products for sale today:</p>
  <ul>
    <li>Tenderloin</li>
    <li>Short ribs</li>
    <li>Beef shin</li>
    <li>Ribeye</li>
  </ul>
</div>

With this component, we want to render the products from the BUTCHER_PRODUCTS array already at the top of the index.js file. React supports the rendering of arrays filled with valid JSX, i.e.:

const ROTTEN_MEAT_PRODUCTS = ["Old Fish", "Sweeney Todd", "Tomatoes?"]

const products = [<li>{ROTTEN_MEAT_PRODUCTS[0]}</li>, <li>ROTTEN_MEAT_PRODUCTS[1]</li>, etc...]
render() {
  return (
    <div>
      { products }
    </div>
  )
}

Whenever we want to pass a variable into JSX, we need to wrap it in {}. The brackets tell React to resolve everything within the {} with JavaScript and fill in whatever it returns. This is similar to when we have used string interpolation (i.e. #{@doge.name}, ${choux.hobbies}).

What higher order iterator could we use on BUTCHER_PRODUCTS to return that kind of array structure? When a JSX filled array is passed into a render method, React will automatically unpack it to JSX!

Look in the Browser!

While its important to get used to reading React code and asserting its functionality directly, (it's just JavaScript, after all!), we should also make sure our React application looks the way we would like in the browser. In order to do this, serve our application by running npm start. Thereafter, we are able to inspect our results in the browser at whatever port it announces it's running on.

Resources

React Documentation: Components

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