feat(uniqueid): adding uniqueid utility

Author: jeffchew

packages/utilities/src/utilities/index.js

@@ -16,3 +16,4 @@ export * from './sameHeight';
 export * from './serialize';
 export * from './settings';
 export * from './smoothScroll';
+export * from './uniqueid';

packages/utilities/src/utilities/markdownToHtml/__tests__/markdownToHtml.js packages/utilities/src/utilities/markdownToHtml/__tests__/markdownToHtml.test.js

@@ -0,0 +1,17 @@
+import { uniqueid } from '../';
+
+describe('Unique ID utility', () => {
+  it('should generate a unique ID', () => {
+    const id1 = uniqueid();
+    const id2 = uniqueid();
+    expect(id1).toBe('id1');
+    expect(id2).toBe('id2');
+  });
+
+  it('should generate a unique ID with user defined prefix', () => {
+    const id1 = uniqueid('prefix');
+    const id2 = uniqueid('prefix-');
+    expect(id1).toBe('prefix3');
+    expect(id2).toBe('prefix-4');
+  });
+});

packages/utilities/src/utilities/uniqueid/__tests__/uniqueid.test.js

@@ -0,0 +1,8 @@
+/**
+ * Copyright IBM Corp. 2016, 2018
+ *
+ * This source code is licensed under the Apache-2.0 license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+export { default as uniqueid } from './uniqueid';

packages/utilities/src/utilities/uniqueid/index.js

@@ -0,0 +1,19 @@
+/**
+ * Stores the latast id to increment
+ * @type {number} Number stored for the next ID
+ * @private
+ */
+let _lastId = 0;
+
+/**
+ * Creates a unique ID to use
+ *
+ * @param {string=} prefix Prefix to set for the id
+ * @returns {string} Unique ID
+ */
+function uniqueid(prefix = 'id') {
+  _lastId++;
+  return `${prefix}${_lastId}`;
+}
+
+export default uniqueid;