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What is !!?


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Hello @masha

!! in JavaScript is an operator that is used to cast variables to boolean. For instance, 1 will cast to true if we do !!1. Similarly, 0 will cast to false if we do !!0.

Hope this helps!

Thanks.
Than what is !1 or !0?

! reverses the truth value. !1 would evaluate to 0 and vice versa for !0.