5 hands-on exercises and 5 find-the-bug challenges for the JavaScript Arrow Functions lesson. Every one is checked automatically in the browser — write the code, run it, and the tests tell you what still fails.
Write an arrow function that doubles a number. Show it for 25.
Write the same doubling function in one line with no braces. Show it for 33.
Write an arrow function that adds two numbers. Show 8 plus 9.
Use an arrow function with map to square each number, then join with commas.
Return an object from a one-line arrow function and show its name.
An arrow function needs the arrow between the parameters and the body.
With braces the function must return explicitly.
Ready to write the code?
The editor, the automatic checks and the worked solutions open up with an account.
Open the workspaceWith two parameters the round brackets are required.
Without round brackets the braces are treated as a function body.
An arrow function has no this, so it cannot see the object.