feat(core): add a utility function that checks if a value is undefined or empty string

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);
+    });
+  });
 });

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 === '';
+}