Write an IIFE — practice exercise

What you'll be asked to do

1. 1.Write an IIFEexercise · easy · 10 min

   Use an IIFE to work out 6 times 7 and store the answer.

   Passes when: #out should show 42.

2. 2.Pass an argumentexercise · easy · 10 min · practice plan

   Pass the name Ada into an IIFE and return a greeting.

   Passes when: #out should show Hello Ada.

3. 3.Keep a variable privateexercise · easy · 10 min · practice plan

   Show that a variable inside an IIFE cannot be seen outside.

   Passes when: #out should show undefined.

4. 4.Return an objectexercise · easy · 10 min · practice plan

   Return a config object from an IIFE and show its version.

   Passes when: #out should show 1.0.

5. 5.An arrow IIFEexercise · medium · 10 min · practice plan

   Write the same idea as an arrow IIFE returning the word ready.

   Passes when: #out should show ready.

6. 6.Fix the IIFE that never runsbug fix · easy · 8 min

   Without the final brackets the function is stored, not called.

   Passes when: #out should show 42.

7. 7.Fix the argument in the wrong bracketsbug fix · easy · 8 min · practice plan

   The argument belongs in the calling brackets.

   Passes when: #out should show Hello Ada.

8. 8.Fix the leaked variablebug fix · easy · 8 min · practice plan

   The variable is declared outside, so it is not private.

   Passes when: #out should show undefined.

9. 9.Fix the missing returnbug fix · easy · 8 min · practice plan

   The IIFE builds the object but never gives it back.

   Passes when: #out should show 1.0.

10. 10.Fix the arrow IIFE syntaxbug fix · easy · 8 min · practice plan

    The arrow function is never invoked.

    Passes when: #out should show ready.

Between them these tasks cover Immediately invoked functions, Private scope and Module pattern.

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