Merge branch 'master' into add-is-gen

index.js

@@ -134,11 +134,13 @@ is.plainObject = x => {
 	// eslint-disable-next-line no-return-assign
 	return getObjectType(x) === 'Object' &&
 		(prototype = Object.getPrototypeOf(x), prototype === null ||
-		prototype === Object.getPrototypeOf({}));
+			prototype === Object.getPrototypeOf({}));
 };
 
 is.iterable = x => !is.null(x) && !is.undefined(x) && typeof x[Symbol.iterator] === 'function';
 
+is.class = x => typeof x === 'function' && x.toString().startsWith('class ');
+
 const typedArrayTypes = new Set([
 	'Int8Array',
 	'Uint8Array',

readme.md

@@ -118,6 +118,10 @@ JavaScript primitives are as follows: `null`, `undefined`, `string`, `number`, `
 An object is plain if it's created by either `{}`, `new Object()`, or `Object.create(null)`.
 
 ##### .iterable(value)
+##### .class(value)
+
+Returns `true` for instances created by a ES2015 class.
+
 ##### .typedArray(value)
 
 

test.js

@@ -287,6 +287,18 @@ test('is.iterable', t => {
 	t.false(m.iterable({}));
 });
 
+test('is.class', t => {
+	class Foo {}
+	const classDeclarations = [
+		Foo,
+		class Bar extends Foo {}
+	];
+
+	for (const x of classDeclarations) {
+		t.true(m.class(x));
+	}
+});
+
 test('is.typedArray', t => {
 	const typedArrays = [
 		new Int8Array(),