feat(guards): isBoolean

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

src/guards/__tests__/is-boolean.spec-d.ts

@@ -0,0 +1,12 @@
+/**
+ * @file Type Tests - isBoolean
+ * @module tutils/guards/tests/unit-d/isBoolean
+ */
+
+import type testSubject from '../is-boolean'
+
+describe('unit-d:guards/isBoolean', () => {
+  it('should guard boolean', () => {
+    expectTypeOf<typeof testSubject>().guards.toBeBoolean()
+  })
+})

src/guards/__tests__/is-boolean.spec.ts

@@ -0,0 +1,20 @@
+/**
+ * @file Unit Tests - isBoolean
+ * @module tutils/guards/tests/unit/isBoolean
+ */
+
+import testSubject from '../is-boolean'
+
+describe('unit:guards/isBoolean', () => {
+  it('should return false if value is not a boolean', () => {
+    expect(testSubject(faker.number.int())).to.be.false
+  })
+
+  it('should return true if value is a boolean', () => {
+    // Arrange
+    const cases: Parameters<typeof testSubject>[] = [[false], [true]]
+
+    // Act + Expect
+    cases.forEach(([value]) => expect(testSubject(value)).to.be.true)
+  })
+})

src/guards/index.ts

@@ -5,6 +5,7 @@
 
 export { default as isAppEnv } from './is-app-env'
 export { default as isBigInt } from './is-big-int'
+export { default as isBoolean } from './is-boolean'
 export { default as isBooleanish } from './is-booleanish'
 export { default as isEmptyString } from './is-empty-string'
 export { default as isEmptyValue } from './is-empty-value'

src/guards/is-boolean.ts

@@ -0,0 +1,16 @@
+/**
+ * @file Type Guards - isBoolean
+ * @module tutils/guards/isBoolean
+ */
+
+/**
+ * Checks if the given `value` is a boolean.
+ *
+ * @param {unknown} value - Value to evaluate
+ * @return {value is boolean} `true` if `value` is a boolean
+ */
+const isBoolean = (value: unknown): value is boolean => {
+  return typeof value === 'boolean'
+}
+
+export default isBoolean

src/guards/is-booleanish.ts

@@ -4,6 +4,7 @@
  */
 
 import type { Booleanish } from '#src/types'
+import isBoolean from './is-boolean'
 
 /**
  * Checks if the given `value` is a boolean, `'false'`, or `'true'`.
@@ -12,7 +13,7 @@ import type { Booleanish } from '#src/types'
  * @return {value is Booleanish} `true` if `value` is {@linkcode Booleanish}
  */
 const isBooleanish = (value: unknown): value is Booleanish => {
-  return typeof value === 'boolean' || value === 'false' || value === 'true'
+  return isBoolean(value) || value === 'false' || value === 'true'
 }
 
 export default isBooleanish