feat: add functional utilities

README.md

@@ -2,8 +2,8 @@
 
 [![NPM version](https://img.shields.io/npm/v/@zakodium/utils.svg)](https://www.npmjs.com/package/@zakodium/utils)
 [![npm download](https://img.shields.io/npm/dm/@zakodium/utils.svg)](https://www.npmjs.com/package/@zakodium/utils)
-[![test coverage](https://img.shields.io/codecov/c/github/@zakodium/utils.svg)](https://codecov.io/gh/@zakodium/utils)
-[![license](https://img.shields.io/npm/l/@zakodium/utils.svg)](https://github.com/@zakodium/utils/blob/main/LICENSE)
+[![test coverage](https://img.shields.io/codecov/c/github/zakodium/utils.svg)](https://app.codecov.io/gh/zakodium/utils)
+[![license](https://img.shields.io/github/license/zakodium/utils.svg)](https://github.com/zakodium/utils/blob/main/LICENSE)
 
 Small utilities by zakodium for zakodium.
 
@@ -29,20 +29,6 @@ assertDefinedNotNull(value); // throws if value is null or undefined
 
 - [API Reference](https://zakodium.github.io/utils/)
 
-### Assertions
-
-With types mutations.
-
-- `function assert(value: unknown, message?: string | (() => string)): asserts value;`
-- `function assertUnreachable(value: never): never;`
-- `function assertDefined<T>(value: T): asserts value is Exclude<T, undefined>;`
-- `function assertDefinedNotNull<T>(value: T): asserts value is Exclude<T, null | undefined>;`
-
-### Casting
-
-- `function is<Output>(value: unknown, condition: boolean): value is Output;`
-- `function cast<Output>(value: unknown): asserts value is Output;`
-
 ## Features that could be added later
 
 - Iterable helpers like `map`, `filter` and so on.

package.json

@@ -41,10 +41,10 @@
   },
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/@zakodium/utils.git"
+    "url": "git+https://github.com/zakodium/utils.git"
   },
   "bugs": {
-    "url": "https://github.com/@zakodium/utils/issues"
+    "url": "https://github.com/zakodium/utils/issues"
   },
-  "homepage": "https://github.com/@zakodium/utils#readme"
+  "homepage": "https://github.com/zakodium/utils#readme-ov-file"
 }

src/functional/identity.test.ts

@@ -0,0 +1,29 @@
+import { expect, test } from 'vitest';
+
+import { identity } from './identity.ts';
+
+test('should return undefined', () => {
+  expect(identity(undefined)).toBeUndefined();
+});
+
+test('should return null', () => {
+  expect(identity(null)).toBeNull();
+});
+
+test('should return 0', () => {
+  expect(identity(0)).toBe(0);
+});
+
+test('should return false', () => {
+  expect(identity(false)).toBe(false);
+});
+
+test('should return string', () => {
+  expect(identity('foo')).toBe('foo');
+});
+
+test('should return object as-is', () => {
+  const object = {};
+
+  expect(identity(object)).toBe(object);
+});

src/functional/identity.ts

@@ -0,0 +1,7 @@
+/**
+ * Identity function.
+ * @param value
+ */
+export function identity<T>(value: T): T {
+  return value;
+}

src/functional/index.ts

@@ -0,0 +1,2 @@
+export * from './noop.ts';
+export * from './identity.ts';

src/functional/noop.test.ts

@@ -0,0 +1,10 @@
+import { expect, test } from 'vitest';
+
+import { noop } from './noop.ts';
+
+test('noop should always returns undefined', () => {
+  expect(noop()).toBeUndefined();
+
+  // @ts-expect-error check if add truthy arguments continue to return undefined
+  expect(noop({})).toBeUndefined();
+});

src/functional/noop.ts

@@ -0,0 +1,4 @@
+/**
+ * No operation function.
+ */
+export function noop() {}

src/index.ts

@@ -1 +1,2 @@
 export * from './types/index.ts';
+export * from './functional/index.ts';