What's the difference between double exclamation operator and Boolean() in JavaScript? [duplicate]

Question

I know that !!variable will convert variable into a boolean value and the function Boolean(), according to the ecma262 spec, will also perform a type conversion by calling ToBoolean(value).

My question is: what's the difference? Is !! better in performance than Boolean() ?

Answer 1

They are the same, as the ! operator will call ToBoolean() internally on its operand, and then flip that returned value, while Boolean() will call ToBoolean() internally on its argument.