React Initial State Lab


In this lab, you'll set initial state in a React component and distinguish between state and props.


Follow the steps below and create two components, ImageSlider and Bomb. Currently, Bomb.js and ImageSlider.js don't contain any code, so if you run learn, you'll get an error. This is because our tests are trying to import and use these components before they've been written.

So, before we continue, your first task is to create a simple components for both ImageSlider and Bomb:

  • In the src/ImageSlider.js file, create an ImageSlider React component.
  • In the src/Bomb.js file, create a Bomb React component.

These components will need a valid render method to allow for our tests to properly import and use them.

Image slider

Let's pretend we're making an awesome slider for our new portfolio site. Naturally, we'll use React to do so! We have to start somewhere, so in this lab we'll just focus on setting up the initial state of the slider.

  1. Its initial state should have a property called currentSlideIndex that starts at 0.
  2. It should only render out the text 'I am on slide <CURRENT_SLIDE>', where <CURRENT_SLIDE> is the value of this.state.currentSlideIndex.

A bomb timer

Take a moment to think about what a bomb does and how it works. Don't get all into the nitty gritty — what we're going to focus on right now is the timer.

Let's create a component that represents a bomb timer that counts down until it reaches 0. However, the only thing we're going to focus on right now is setting the initial state of the bomb: the amount of seconds left on the timer. Since bomb timers can differ, we'll pass in a prop to our Bomb component to determine what the starting count should be.

  1. Its initial state should have a property called secondsLeft.
  2. The initial value of secondsLeft is set by passing in an initialCount prop to the Bomb component. Don't forget to pass the argument props into the constructor (i.e., constructor(props)).
  3. It should render the text '<SECONDS_LEFT> seconds left before I go boom!', where <SECONDS_LEFT> is the value of secondsLeft.
  4. If secondsLeft equals 0, it should render 'Boom!' instead.


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