feat(types): IsObject, IfObject

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

src/types/__tests__/if-object.spec-d.ts

@@ -0,0 +1,19 @@
+/**
+ * @file Type Tests - IfObject
+ * @module tutils/types/tests/unit-d/IfObject
+ */
+
+import type TestSubject from '../if-object'
+
+describe('unit-d:types/IfObject', () => {
+  type False = false
+  type True = true
+
+  it('should equal False if IsObject<T> extends false', () => {
+    expectTypeOf<TestSubject<string, True, False>>().toEqualTypeOf<False>()
+  })
+
+  it('should equal True if IsObject<T> extends true', () => {
+    expectTypeOf<TestSubject<object, True, False>>().toEqualTypeOf<True>()
+  })
+})

src/types/__tests__/is-object.spec-d.ts

@@ -0,0 +1,32 @@
+/**
+ * @file Type Tests - IsObject
+ * @module tutils/types/tests/unit-d/IsObject
+ */
+
+import type Fn from '../fn'
+import type TestSubject from '../is-object'
+import type ObjectCurly from '../object-curly'
+import type Primitive from '../primitive'
+
+describe('unit-d:types/IsObject', () => {
+  it('should equal false if [T] does not extend [object]', () => {
+    expectTypeOf<TestSubject<Primitive>>().toEqualTypeOf<false>()
+    expectTypeOf<TestSubject<Primitive | object>>().toEqualTypeOf<false>()
+  })
+
+  it('should equal false if T is any', () => {
+    expectTypeOf<TestSubject<any>>().toEqualTypeOf<false>()
+  })
+
+  it('should equal false if T is never', () => {
+    expectTypeOf<TestSubject<never>>().toEqualTypeOf<false>()
+  })
+
+  it('should equal true if [T] extends [object]', () => {
+    expectTypeOf<TestSubject<Fn>>().toEqualTypeOf<true>()
+    expectTypeOf<TestSubject<ObjectCurly>>().toEqualTypeOf<true>()
+    expectTypeOf<TestSubject<RegExp>>().toEqualTypeOf<true>()
+    expectTypeOf<TestSubject<object>>().toEqualTypeOf<true>()
+    expectTypeOf<TestSubject<readonly string[]>>().toEqualTypeOf<true>()
+  })
+})

src/types/if-object.ts

@@ -0,0 +1,19 @@
+/**
+ * @file Type Definitions - IfObject
+ * @module tutils/types/IfObject
+ */
+
+import type IsObject from './is-object'
+
+/**
+ * Returns a type that indicates if `T` is an `object`.
+ *
+ * @see {@linkcode IsObject}
+ *
+ * @template T - Type to evaluate
+ * @template True - Type if `T` is an `object`
+ * @template False - Type if `T` is not an `object`
+ */
+type IfObject<T, True, False> = IsObject<T> extends true ? True : False
+
+export type { IfObject as default }

src/types/index.ts

@@ -44,6 +44,7 @@ export type { default as IfNil } from './if-nil'
 export type { default as IfNull } from './if-null'
 export type { default as IfNumber } from './if-number'
 export type { default as IfNumeric } from './if-numeric'
+export type { default as IfObject } from './if-object'
 export type { default as IfPrimitive } from './if-primitive'
 export type { default as IfString } from './if-string'
 export type { default as IfSymbol } from './if-symbol'
@@ -68,6 +69,7 @@ export type { default as IsNil } from './is-nil'
 export type { default as IsNull } from './is-null'
 export type { default as IsNumber } from './is-number'
 export type { default as IsNumeric } from './is-numeric'
+export type { default as IsObject } from './is-object'
 export type { default as IsPrimitive } from './is-primitive'
 export type { default as IsString } from './is-string'
 export type { default as IsSymbol } from './is-symbol'

src/types/is-object.ts

@@ -0,0 +1,15 @@
+/**
+ * @file Type Definitions - IsObject
+ * @module tutils/types/IsObject
+ */
+
+import type IfAnyOrNever from './if-any-or-never'
+
+/**
+ * Returns a boolean indicating if `T` is an `object`.
+ *
+ * @template T - Type to evaluate
+ */
+type IsObject<T> = IfAnyOrNever<T, false, [T] extends [object] ? true : false>
+
+export type { IsObject as default }