add support for is.generator & is.generatorFunction

index.js

@@ -81,6 +81,10 @@ is.promise = x => {
 		);
 };
 
+is.generator = x => x && typeof x.next === 'function' && typeof x.throw === 'function';
+
+is.generatorFunction = x => x.constructor.name === 'GeneratorFunction';
+
 is.regExp = x => getObjectType(x) === 'RegExp';
 is.date = x => getObjectType(x) === 'Date';
 is.error = x => getObjectType(x) === 'Error';

readme.md

@@ -78,6 +78,9 @@ Keep in mind that [functions are objects too](https://developer.mozilla.org/en-U
 
 Returns `true` for any object with a `.then()` and `.catch()` method. Prefer this one over `.nativePromise()` as you usually want to allow userland promise implementations too.
 
+##### .generator(value)
+##### .generatorFunction(value)
+
 ##### .map(value)
 ##### .set(value)
 ##### .weakMap(value)

test.js

@@ -82,7 +82,7 @@ const types = new Map([
 	['integer', 6]
 ]);
 
-// This ensure a certain method matches only the types
+// This ensures a certain method matches only the types
 // it's supposed to and none of the other methods' types
 const testType = (t, type, exclude) => {
 	for (const [key, value] of types) {
@@ -166,6 +166,20 @@ if (isNode8orHigher) {
 	});
 }
 
+test('is.generator', t => {
+	const genObj = (function * () {
+		yield 42;
+	})();
+	t.true(m.generator(genObj));
+});
+
+test('is.generatorFunction', t => {
+	const gen = function * () {
+		yield 42;
+	};
+	t.true(m.generatorFunction(gen));
+});
+
 test('is.map', t => {
 	testType(t, 'map');
 });