Cannot read property 'presets' of undefined

Tell us what’s happening:
TypeError: Cannot read property ‘presets’ of undefined
why this error appears?
i am totally confused

Your code so far

function dropElements(arr, func) {
var a=[...arr];
return arr;

dropElements([1, 2, 3], function(n) {return n < 3; });

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.113 Safari/537.36.

Challenge: Drop it

Link to the challenge:

I don’t get the error you are referring to when i run your code. It is important to read and understand the task before attempting. Your code is not close to what is expected of you.

I’m not able to generate that error. If you’re seeing it in your browser console my best bet is that either your browser cache ended up in a weird state (refresh the page and maybe clear your local storage) or you have an extension running that has a bug.

I believe the message is coming from Babel and is likely a cache issue. As said, resetting the challenge and clearing the cache should help.