Sometimes brute force is the way to go.
...
This might not be that time, but sometimes it is! I also used this solution.

xD

:D i love this one

Bitwise operators.

can someone explain that ?

gj

imo 2 hard 4 kyu7

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Seems fixed to me.

no need for ternary

(acc + val) % 3 === 0 will return true if it's true

Not a issue, it's a question.

Also, have you even read the test inputs before filing a issue? It shows pretty clearly your code fails for n<1.

Not a issue, this is a question.

Read the descriptions; you need to check if the input is a string.

Please raise code questions as a question instead of an issue.

By the way, have you checked that the input is actually a string?

Not a issue