React Data Fetching: ISS Tracker

This challenge asks you to refactor the existing code of the ISS Tracker to use SWR. You will need to fetch on interval and refetch on click of a button.

Task

• Start the development server and make yourself familiar with the application.
• Switch to the ISSTracker component: it features a coords state, a getISSCoords function and a useEffect to fetch data on interval.

Fetching on load

• Comment out all unnecessary code:

  • the coords state,
  • the getISSCoords function,
  • the useEffect,
  • for now: the onRefresh prop passed to the Controls component (you will adapt this in a minute).

• Implement fetching of the same data with SWR.

  • SWR is already installed, so you just have to import it.
  • Handle the isLoading and error states provided by SWR as well.
  • Make sure data is defined before working with it.
  • Remember to adapt the fetcher function to create a proper error state as explained in the SWR docs.
  • Note: SWR needs you to destructure a data object, but the Map and Controls component need longitude and latitude as separate props; how can you simply pass the coordinates from data without changing the Map/index.js and Controls/index.js files? (Hint: there are several ways to do this!)

✨ You should now see the exact position of the ISS again when refreshing the page!

Implement interval

• Refetch the data of the ISS on an interval of 5 seconds. See the SWR docs to find help how to do it.

Refetch on button click

The only thing not working yet is the "Refresh" button because the getISSCords function does not exist anymore.

• Destructure the mutate function provided by the useSWR hook.
• Pass it to the onRefresh prop of the Controls component. You can use an inline function as in onReload={() => handleReload()}.

✨ Congratulations, you can now see the exact position of the ISS whenever you want with the help of SWR!

Notes

• You only have to touch the ./components/ISSTracker/index.js file.

Development

Local Development

To work locally, please install the dependencies using npm i first.

Run npm run dev to start a development server and open the displayed URL in a browser.

Use npm run test to run the tests.

CodeSandbox Cloud

Select the "Preview: 3000" tab to view this project.

Select the "Tests: logs" tab to view the tests.

The npm run dev and npm run test scripts run automatically.

Scripts

You can use the following commands:

• npm run dev to start a development server
• npm run build to build the project
• npm run start to start a production server
• npm run test to run the tests
• npm run lint to run the linter