Like other checkers, returns true if `value` is falsey. Strings, arrays and `arguments` objects with a length of `0`, and objects with no own enumerable properties are considered falsey. Will also check against user-defined "special cases".

Test if a value is falsy.

Test if a value is truthy.

Test if a value is an array-like object containing only truthy values.

Test if a value is an array-like object containing only falsy values.