Add is.fortyTwo

readme.md

@@ -471,6 +471,10 @@ is.urlSearchParams(searchParams);
 //=> true
 ```
 
+#### .fortyTwo(value)
+
+Return `true` if `value` is `42`.
+
 ##### .any(predicate | predicate[], ...values)
 
 Using a single `predicate` argument, returns `true` if **any** of the input `values` returns true in the `predicate`:

source/index.ts

@@ -368,6 +368,8 @@ is.formData = (value: unknown): value is FormData => isObjectOfType<FormData>('F
 
 is.urlSearchParams = (value: unknown): value is URLSearchParams => isObjectOfType<URLSearchParams>('URLSearchParams')(value);
 
+is.fortyTwo = (value: unknown): value is 42 => value === 42;
+
 export type Predicate = (value: unknown) => boolean;
 
 type ArrayMethod = (fn: (value: unknown, index: number, array: unknown[]) => boolean, thisArg?: unknown) => boolean;

test/test.ts

@@ -1507,6 +1507,11 @@ test('is.nonEmptyMap', t => {
 	});
 });
 
+test('is.fortyTwo', t => {
+	t.true(is.fortyTwo(42));
+	t.false(is.fortyTwo(43));
+});
+
 test('is.propertyKey', t => {
 	t.true(is.propertyKey('key'));
 	t.true(is.propertyKey(42));