From 5655ce433189efd6d93a58fe3719fd32164eb88d Mon Sep 17 00:00:00 2001
From: Arman Ozak <arman@armanozak.com>
Date: Fri, 20 Mar 2020 14:00:00 +0300
Subject: [PATCH] feat(core): add a utility function that checks if a value is
 undefined or empty string

---
 .../core/src/lib/tests/common-utils.spec.ts    | 18 +++++++++++++++++-
 .../core/src/lib/utils/common-utils.ts         |  4 ++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/npm/ng-packs/packages/core/src/lib/tests/common-utils.spec.ts b/npm/ng-packs/packages/core/src/lib/tests/common-utils.spec.ts
index 98c6614987..60280e396b 100644
--- a/npm/ng-packs/packages/core/src/lib/tests/common-utils.spec.ts
+++ b/npm/ng-packs/packages/core/src/lib/tests/common-utils.spec.ts
@@ -1,4 +1,4 @@
-import { noop } from '../utils';
+import { isUndefinedOrEmptyString, noop } from '../utils';
 
 describe('CommonUtils', () => {
   describe('#noop', () => {
@@ -7,4 +7,20 @@ describe('CommonUtils', () => {
       expect(noop()()).toBeUndefined();
     });
   });
+
+  describe('#isUndefinedOrEmptyString', () => {
+    test.each`
+      value        | expected
+      ${null}      | ${false}
+      ${0}         | ${false}
+      ${true}      | ${false}
+      ${'x'}       | ${false}
+      ${{}}        | ${false}
+      ${[]}        | ${false}
+      ${undefined} | ${true}
+      ${''}        | ${true}
+    `('should return $expected when given parameter is $value', ({ value, expected }) => {
+      expect(isUndefinedOrEmptyString(value)).toBe(expected);
+    });
+  });
 });
diff --git a/npm/ng-packs/packages/core/src/lib/utils/common-utils.ts b/npm/ng-packs/packages/core/src/lib/utils/common-utils.ts
index 756d3a34dd..b8609be130 100644
--- a/npm/ng-packs/packages/core/src/lib/utils/common-utils.ts
+++ b/npm/ng-packs/packages/core/src/lib/utils/common-utils.ts
@@ -3,3 +3,7 @@ export function noop() {
   const fn = function() {};
   return fn;
 }
+
+export function isUndefinedOrEmptyString(value: unknown): boolean {
+  return value === undefined || value === '';
+}