Add ES module example

examples/index.mjs

@@ -0,0 +1,29 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+import stdlib from './../lib/index.js';
+
+// List sub-namespaces:
+var keys = stdlib.utils.objectKeys( stdlib );
+console.log( keys );
+
+// Compute the value of sine:
+var y = stdlib.math.base.special.sin( 3.14 );
+console.log( y );