Added IS.NOT function, which returns the reverse IS

index.js

@@ -15,7 +15,7 @@ const _is = {
  * Returns `true` if val is an array; `false` otherwise.
  * typeCheck can be one of:
  * - Function -- in this case it has to be a function from is object. Each value in array will be checked vs this function
- * - Array -- in this case it has to be a valid argument for is function
+ * - Array -- in this case it has to be a valid argument for `is` function
  *
  * @param {*} val
  * @param {Function|Array} typeCheck?
@@ -82,17 +82,59 @@ function is(val, types) {
   return false;
 }
 
+is.not = function(val, types) {
+  return !is(val, types);
+};
+
 is.string = _is.string;
+is.not.string = function() {
+  return !_is.string(...arguments);
+};
+
 is.array = _is.array;
+is.not.array = function() {
+  return !_is.array(...arguments);
+};
+
 is.numeric = _is.numeric;
+is.not.numeric = function() {
+  return !_is.numeric(...arguments);
+};
+
 is.object = _is.object;
+is.not.object = function() {
+  return !_is.object(...arguments);
+};
+
 is.null = _is.null;
+is.not.null = function() {
+  return !_is.null(...arguments);
+};
+
 is.undefined = _is.undefined;
+is.not.undefined = function() {
+  return !_is.undefined(...arguments);
+};
+
 is.callable = _is.callable;
+is.not.callable = function() {
+  return !_is.callable(...arguments);
+};
+
 is.emptyString = _is.emptyString;
+is.not.emptyString = function() {
+  return !_is.emptyString(...arguments);
+};
+
 is.keyValuePair = _is.keyValuePair;
+is.not.keyValuePair = function() {
+  return !_is.keyValuePair(...arguments);
+};
 
 is.instance = _is.instance;
+is.not.instance = function() {
+  return !_is.instance(...arguments);
+};
 
 module.exports = {
   is,

test/test.js

 const { is, force } = require('../index');
 
-// console.log([
-//   is.array(['foo', 'bar']),
-//   is.emptyString(''),
-//   is.callable(() => null),
-//   is.instance([], Object),
-//   is.null(null),
-//   is.numeric('42'),
-//   is.object({ foo: 'bar' }),
-//   is.string('halo'),
-//   is.undefined(undefined)
-// ]);
+console.log(is.not.array(['foo', 'bar']));
+console.log(is.not.emptyString(''));
+console.log(is.not.callable(() => null));
+console.log(is.not.instance([], Object));
+console.log(is.not.null(null));
+console.log(is.not.numeric('42'));
+console.log(is.not.object({ foo: 'bar' }));
+console.log(is.not.string('halo'));
+console.log(is.not.undefined(undefined));
 
 // console.log(is.array(['', '2', ''], 'emptyString'));
 
-console.log(is.keyValuePair({ key: 'value' }));
-console.log(is.keyValuePair({ key: 'value', key2: 'value2' }));
+// console.log(is.keyValuePair({ key: 'value' }));
+// console.log(is.keyValuePair({ key: 'value', key2: 'value2' }));