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Javascript “Bang, Bang. I Shot You Down” - Use of Double Bangs (!!) in Javascript.
How to keep from getting shot down while using double bangs
TLDR;
The !! (double bang) logical operators return a value’s truthy value.
Javascript ‘Truthy’ Values
In Javascript, every value has an associated boolean, true or false, value. For example, a null value has an associated boolean value of false. A string value, such as abc has an associated boolean value of true.
Values that are associated with boolean true are said to be truthy. Values that are associated with boolean false values are said to be falsy.
A full list of truthy values can be found here:
A full list of falsy values can be found here:
Boolean Operations
Certain operations, like conditional if statements, will elect to use the associated boolean true/false value instead of the value itself. In these cases, we can say that the value is being used in a boolean context and will be coerced, or forced to, its associated true/false value.
The First Shot — A Single Bang!
In Javascript, the exclamation mark (“!”) symbol, called a “bang,” is the logical “not” operator. Placed in front of a boolean value it will reverse the value, returning the opposite.
