feat(utils): isArray

Signed-off-by: Lexus Drumgold <[email protected]>

src/utils/__tests__/is-array.spec-d.ts

@@ -0,0 +1,14 @@
+/**
+ * @file Type Tests - isArray
+ * @module tutils/utils/tests/unit-d/isArray
+ */
+
+import type testSubject from '../is-array'
+
+describe('unit-d:utils/isArray', () => {
+  it('should guard T[] | readonly T[]', () => {
+    expectTypeOf<typeof testSubject>().guards.toEqualTypeOf<
+      unknown[] | readonly unknown[]
+    >()
+  })
+})

src/utils/__tests__/is-array.spec.ts

@@ -0,0 +1,16 @@
+/**
+ * @file Unit Tests - isArray
+ * @module tutils/utils/tests/unit/isArray
+ */
+
+import testSubject from '../is-array'
+
+describe('unit:utils/isArray', () => {
+  it('should return false if value is not an array', () => {
+    expect(testSubject(faker.datatype.boolean())).to.be.false
+  })
+
+  it('should return true if value is an array', () => {
+    expect(testSubject([0, 1, 2, 3, 4])).to.be.true
+  })
+})

src/utils/index.ts

@@ -4,6 +4,7 @@
  */
 
 export { default as isAppEnv } from './is-app-env'
+export { default as isArray } from './is-array'
 export { default as isBigInt } from './is-big-int'
 export { default as isBoolean } from './is-boolean'
 export { default as isBooleanish } from './is-booleanish'

src/utils/is-array.ts

@@ -0,0 +1,20 @@
+/**
+ * @file Utilities - isArray
+ * @module tutils/utils/isArray
+ */
+
+import isObject from './is-object'
+
+/**
+ * Checks if `value` is an array.
+ *
+ * @template T - Array item type
+ *
+ * @param {unknown} value - Value to check
+ * @return {value is ReadonlyArray<T> | T[]} `true` if `value` is an array
+ */
+function isArray<T>(value: unknown): value is T[] | readonly T[] {
+  return isObject(value) && Reflect.get(value, 'constructor') === Array
+}
+
+export default isArray