Logical NOT Operator (!)
Performs logical negation on an expression.
!expression
Arguments
- expression
Any expression.
Remarks
The following table illustrates how the result is determined.
If expression coerces to |
Then result is |
---|---|
true |
false |
false |
true |
All unary operators, such as the ! operator, evaluate expressions as follows:
If applied to undefined or null expressions, a run-time error is raised.
Objects are converted to strings.
Strings are converted to numbers if possible. If not, a run-time error is raised.
Boolean values are treated as numbers (0 if false, 1 if true).
The operator is applied to the resulting number.
For the ! operator, if expression is nonzero, result is zero. If expression is zero, result is 1.