Create and resolve a promise — practice exercise

What you'll be asked to do

1. 1.Create and resolve a promiseexercise · easy · 10 min

   Make a promise that resolves with a name and report it.

   Passes when: #out should show got Ada.

2. 2.Reject a promiseexercise · easy · 10 min · practice plan

   Reject a promise and report the reason with catch.

   Passes when: #out should show failed: no network.

3. 3.Use Promise.resolveexercise · easy · 10 min · practice plan

   Use a ready-made resolved promise and report its value.

   Passes when: #out should show here.

4. 4.Show it settles onceexercise · easy · 10 min · practice plan

   Resolve twice and show only the first value is kept.

   Passes when: #out should show first.

5. 5.Show then runs laterexercise · medium · 10 min · practice plan

   Report the order of a synchronous line and a then handler.

   Passes when: #out should show sync then promise.

6. 6.Fix the promise never resolvedbug fix · easy · 8 min

   Nothing calls resolve, so the handler never runs.

   Passes when: #out should show got Ada.

7. 7.Fix then used for a rejectionbug fix · easy · 8 min · practice plan

   A rejected promise is handled by catch, not by then.

   Passes when: #out should show failed: no network.

8. 8.Fix the value read outside the handlerbug fix · easy · 8 min · practice plan

   The value only exists inside then.

   Passes when: #out should show ready.

9. 9.Fix reject used where resolve belongsbug fix · easy · 8 min · practice plan

   The work succeeded, so the promise should resolve.

   Passes when: #out should show worked.

10. 10.Fix then called on the valuebug fix · easy · 8 min · practice plan

    then belongs to the promise, not to what it resolves with.

    Passes when: #out should show here.

Between them these tasks cover Promise, resolve and reject and then.

Looking for a different chapter? See every practice set, or switch to the interview theory questions.