fix: ignore function types

Author: lukeed

src/index.js

@@ -8,7 +8,7 @@ function toVal(mix) {
 					str += y;
 				}
 			}
-		} else if (typeof mix !== 'boolean') {
+		} else if (typeof mix !== 'boolean' && !mix.call) {
 			str && (str += ' ');
 			str += mix;
 		}

test/index.js

@@ -63,3 +63,11 @@ test('arrays (variadic)', t => {
 	t.is(fn(['foo'], null, ['baz', ''], true, '', []), 'foo baz');
 	t.end();
 });
+
+test('functions', t => {
+	const foo = () => {};
+	t.is(fn(foo, 'hello'), 'hello');
+	t.is(fn(foo, 'hello', fn), 'hello');
+	t.is(fn(foo, 'hello', [[fn], 'world']), 'hello world');
+	t.end();
+});