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Updated: May 31, 2026

Api Loading State

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Conclusion

Api Loading State — free browser-based JavaScript practice

■ What this exercise teaches Output "Loading..." before fetch and "Done" after success, using console.log.

Why it matters in real projects

With async code, log in order so the user can see the current state. Similar patterns appear daily in code review and production UI work.

Step-by-step workflow

1. Read the guide and understand the goal of "Api Loading State" 2. Review the JavaScript editor pane and start from the starter code 3. Open hints if stuck; compare your diff with the sample solution 4. Click Run and inspect preview/console output 5. Auto-check looks for output containing: Loading, Done. 6. After success, continue with adjacent exercises in the same category

Core concept explained

With async code, log in order so the user can see the current state.

Technical focus

Key CSS properties: https.

Hint before you peek at the solution

Log Loading first, then Done after await.

Sample solution walkthrough

JavaScript APIs used: console.log, fetch(, async , await . Verify spelling and async/await usage. Explanation: With async code, log in order so the user can see the current state. Hint recap: Log Loading first, then Done after await.

Solution code

📝 Sample code
async function run() {
  console.log('Loading...');
  const res = await fetch('https://jsonplaceholder.typicode.com/posts/1');
  const data = await res.json();
  console.log('Done', data.title);
}
run();

Common mistakes for this exact task

- Skipping the hint: Log Loading first, then Done after await. - Forgetting await res.json() leaves you with a Promise object

Troubleshooting

Q: Preview does not change after Run A: Ensure you edited the JavaScript pane and clicked Run. Q: Looks correct but check fails A: Auto-check looks for output containing: Loading, Done. Look for typos, full-width spaces, or unclosed tags. Q: Console shows errors A: Open DevTools Console and fix bracket/quote mismatches at the reported line. Q: Hard to type on mobile A: Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview / portfolio tips

- Explain the techniques in "Api Loading State" in your own words within 30 seconds - Practice walking through each line of the sample solution on a whiteboard - Connect this task to a real component you would ship - Discuss CSS properties: https - Describe when you use: console.log, fetch(, async

What to do after you pass

Move to the next exercise in the api track, then continue the learning roadmap at /en/learning/api/.

Keywords

Free hands-on exercise covering Loading state, api, advanced, https, console.log, fetch(, async , await , api loading state—search-friendly guide for Api Loading State.

🧪 Try it here — safe to break things

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■ Exercise task

Output "Loading..." before fetch and "Done" after success, using console.log.

Hint if stuck

Log Loading first, then Done after await.

20pt

Loading state

Output "Loading..." before fetch and "Done" after success, using console.log.

Click error to highlight line. ✕=error ⚠=warning ›=log.

Roadmap · All guides

Deep dive

"Api Loading State" is a advanced-level JavaScript exercise. Output "Loading..." before fetch and "Done" after success, using console.log. Run it in-browser with automatic checking.

With async code, log in order so the user can see the current state. Similar patterns appear daily in code review and production UI work.

Pair this with the api roadmap. Exercise #68 reinforces core api skills.

Step-by-step workflow

  1. Read the guide and understand the goal of "Api Loading State"
  2. Review the JavaScript editor pane and start from the starter code
  3. Open hints if stuck; compare your diff with the sample solution
  4. Click Run and inspect preview/console output
  5. Auto-check looks for output containing: Loading, Done.
  6. After success, continue with adjacent exercises in the same category

How to read the sample solution

JavaScript APIs used: console.log, fetch(, async , await . Verify spelling and async/await usage. Explanation: With async code, log in order so the user can see the current state. Hint recap: Log Loading first, then Done after await.

Real-world & career relevance

fetch + JSON appear in most real projects: weather apps, GitHub integrations, headless CMS.

Common mistakes

  • Skipping the hint: Log Loading first, then Done after await.
  • Forgetting await res.json() leaves you with a Promise object
  • Forgetting res.json() after fetch
  • Treating CORS as a code bug
  • No try-catch for network failures

Troubleshooting

Preview does not change after Run
Ensure you edited the JavaScript pane and clicked Run.
Looks correct but check fails
Auto-check looks for output containing: Loading, Done. Look for typos, full-width spaces, or unclosed tags.
Console shows errors
Open DevTools Console and fix bracket/quote mismatches at the reported line.
Hard to type on mobile
Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview & portfolio tips

  • Explain the techniques in "Api Loading State" in your own words within 30 seconds
  • Practice walking through each line of the sample solution on a whiteboard
  • Connect this task to a real component you would ship
  • Discuss CSS properties: https
  • Describe when you use: console.log, fetch(, async

Glossary

fetch
Browser API for HTTP requests.
JSON
Lightweight data interchange format.
CORS
Cross-origin browser security policy.

Keywords covered on this page

Free hands-on exercise covering Loading state, api, advanced, https, console.log, fetch(, async , await , api loading state—search-friendly guide for Api Loading State.

Related dev tools

Learning roadmap

Learning roadmap →

Related exercises

Frequently asked questions

Is "Loading state" free?

This exercise is free and runs entirely in your browser. No account or credit card required.

Difficulty and time?

"Loading state" is level "advanced". Read the guide first; beginners can usually finish within 30 minutes. Allow 5–15 minutes per exercise. Use hints, then the solution if stuck.

What after a correct answer?

After a correct answer, use "Next exercise". When you finish a category, continue on the <a href="/en/learning/api/">learning roadmap</a>.

Works on mobile?

Works on mobile browsers, but typing code is easier on a desktop.

Where are other exercises?

All exercises: <a href="/en/learn/">/en/learn/</a> with category filters.

Key takeaway for "Loading state"?

With async code, log in order so the user can see the current state. Hint: Log Loading first, then Done after await.

Where does API fit?

fetch + JSON appear in most real projects: weather apps, GitHub integrations, headless CMS.

Step-by-step for "Api Loading State"?

1. Read the guide and understand the goal of "Api Loading State"<br />2. Review the JavaScript editor pane and start from the starter code<br />3. Open hints if stuck; compare your diff with the sample solution<br />4. Click Run and inspect preview/console output<br />5. Auto-check looks for output containing: Loading, Done.<br />6. After success, continue with adjacent exercises in the same category

How to read the sample solution?

JavaScript APIs used: console.log, fetch(, async , await . Verify spelling and async/await usage.<br /><br />Explanation: With async code, log in order so the user can see the current state.<br /><br />Hint recap: Log Loading first, then Done after await.

Something is not working?

<strong>Preview does not change after Run</strong> → Ensure you edited the JavaScript pane and clicked Run.<br /><strong>Looks correct but check fails</strong> → Auto-check looks for output containing: Loading, Done. Look for typos, full-width spaces, or unclosed tags.<br /><strong>Console shows errors</strong> → Open DevTools Console and fix bracket/quote mismatches at the reported line.<br /><strong>Hard to type on mobile</strong> → Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Career / interview angle?

Explain the techniques in "Api Loading State" in your own words within 30 seconds Practice walking through each line of the sample solution on a whiteboard Connect this task to a real component you would ship Discuss CSS properties: https Describe when you use: console.log, fetch(, async

Related dev tools?

<a href="/en/tools/json-formatter/">JSON Formatter</a>, <a href="/en/tools/jwt-decode/">JWT Decode</a>, <a href="/en/tools/dns-check/">DNS Check</a>

Prerequisites?

Read the <a href="/en/learning/api/">Learning roadmap</a> chapter first.

Can I change the starter code?

Yes—if it works. Understanding the starter first, then adding minimal diffs, speeds up learning.

What do the points mean?

20pt is a difficulty hint, not a score you must maximize.