feat: add utility isEmptyString

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Expose a few additional types related to snapshots in `ic-management`.
 - Add support for `get_subnet_types_to_subnets` to `@dfinity/cmc`.
 - Support `VotingPowerEconomics`, `potential_voting_power` and `deciding_voting_power` in `@dfinity/nns`.
+- Add utility `emptyString` (the opposite of existing `notEmptyString`).
 
 # 2024.11.27-1230Z
 

packages/utils/README.md

@@ -35,6 +35,7 @@ npm i @dfinity/agent @dfinity/candid @dfinity/principal
 - [isNullish](#gear-isnullish)
 - [nonNullish](#gear-nonnullish)
 - [notEmptyString](#gear-notemptystring)
+- [emptyString](#gear-emptystring)
 - [defaultAgent](#gear-defaultagent)
 - [createAgent](#gear-createagent)
 - [createServices](#gear-createservices)
@@ -121,6 +122,20 @@ Parameters:
 
 [:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/utils/src/utils/nullish.utils.ts#L29)
 
+#### :gear: emptyString
+
+Checks if a given value is null, undefined, or an empty string.
+
+| Function      | Type                                              |
+| ------------- | ------------------------------------------------- |
+| `emptyString` | `(value: string or null or undefined) => boolean` |
+
+Parameters:
+
+- `value`: - The value to check.
+
+[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/utils/src/utils/nullish.utils.ts#L38)
+
 #### :gear: defaultAgent
 
 Get a default agent that connects to mainnet with the anonymous identity.

packages/utils/src/utils/nullish.utils.spec.ts

@@ -1,4 +1,9 @@
-import { isNullish, nonNullish, notEmptyString } from "./nullish.utils";
+import {
+  emptyString,
+  isNullish,
+  nonNullish,
+  notEmptyString,
+} from "./nullish.utils";
 
 describe("nullish-utils", () => {
   describe("isNullish", () => {
@@ -42,4 +47,13 @@ describe("nullish-utils", () => {
       expect(notEmptyString("test")).toBeTruthy();
     });
   });
+
+  describe("emptyString", () => {
+    it("should determine empty", () => {
+      expect(emptyString(null)).toBeTruthy();
+      expect(emptyString(undefined)).toBeTruthy();
+      expect(emptyString("")).toBeTruthy();
+      expect(emptyString("test")).toBeFalsy();
+    });
+  });
 });

packages/utils/src/utils/nullish.utils.ts

@@ -28,3 +28,12 @@ export const nonNullish = <T>(
  */
 export const notEmptyString = (value: string | undefined | null): boolean =>
   nonNullish(value) && value !== "";
+
+/**
+ * Checks if a given value is null, undefined, or an empty string.
+ *
+ * @param {string | undefined | null} value - The value to check.
+ * @returns {boolean} `true` if the value is null, undefined, or an empty string; otherwise, `false`.
+ */
+export const emptyString = (value: string | undefined | null): boolean =>
+  !notEmptyString(value);