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Explore React Hooks

Another developer started a product list page and has requested your help to complete it.

Here are the incomplete features.

  • Click button below each item to see its details in the side panel
  • Show highlight on item itself (so user can see the current selection)
  • Allow user to open/close the side panel
  • Automatically open the side panel if it's closed when an item is clicked
  • Automatically clear the selection when the side panel is closed

Go ahead and clone the starter from the Download link at the bottom of this page. All the changes you need to make will be in src/components/ProductView/ProductView.js.

Prepare

Before starting to change code on a new-to-you project, it is helpful to become familiar with what's already been done. In this case, the original developer used create-react-app as the starting point, then added a few components to display a product list. They determined that the product data will come into the view through a prop named products. (It does not matter where that data comes from as that will be managed outside the component.) Additionally, they finished the layouts in the UI with a box, image, and button for each product as well as a panel on the right side.

When you run the application (npm install followed by npm start), you'll see these UI elements display, but clicking does not do anything. That's where you come in!

When you look at the code in ProductView, you'll find console.log statements in the onClick event handlers. That's a clue some work is needed there. Additionally, you'll find a comment that starts with "TODO". While that might not be the only work required, these will be elements you need to modify.

An astute developer may also notice there are some props on other components that aren't in use yet. The extra effort to find them while you're coming up to speed may save you some time later since you may be able to leverage them to accomplish your tasks.

Next, you need to pick somewhere to start. The panel toggle seems good since it has a TODO comment.

Phase 1: Toggle side panel

To replace a constant with a state variable, you'll want to employ the useState hook. Perhaps, something like this

const [sideOpen, setSideOpen] = useState(true);

Remember to add its import at the top. It will come from the react library.

The application should still run after this change, although VS Code and/or the JavaScript console will probably warn you that setSideOpen is defined but not used.

Go ahead and use it to replace the console.log associated with the toggle UI on the side panel. Remember

  • State variables, like constants, are accessible within the JSX.
  • Likewise, the setting function for any state variable can be called from JSX.
  • Setting a boolean value that's true to false (or false to true) is the purpose of the NOT operator (!).

All this means you could choose to toggle the value with a function call like setSideOpen(!sideOpen).

After replacing the console.log you will likely have code that looks something like this:

<div className="product-side-panel-toggle"
     onClick={() => setSideOpen(!sideOpen)}>

If all the changes are correct, you will be able to click the ">" tab on the side panel to close it. Study the code and see if you can find where it switches to "<". It is common practice in React to use a state variable in multiple UI updates.