feat(types): IsPrimitive, IfPrimitive

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

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

@@ -0,0 +1,20 @@
+/**
+ * @file Type Tests - IfPrimitive
+ * @module tutils/types/tests/unit-d/IfPrimitive
+ */
+
+import type TestSubject from '../if-primitive'
+import type Primitive from '../primitive'
+
+describe('unit-d:types/IfPrimitive', () => {
+  type False = false
+  type True = true
+
+  it('should equal False if IsPrimitive<T> extends false', () => {
+    expectTypeOf<TestSubject<Primitive[], True, False>>().toEqualTypeOf<False>()
+  })
+
+  it('should equal True if IsPrimitive<T> extends true', () => {
+    expectTypeOf<TestSubject<Primitive, True, False>>().toEqualTypeOf<True>()
+  })
+})

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

@@ -0,0 +1,17 @@
+/**
+ * @file Type Tests - IsPrimitive
+ * @module tutils/types/tests/unit-d/IsPrimitive
+ */
+
+import type TestSubject from '../is-primitive'
+import type Primitive from '../primitive'
+
+describe('unit-d:types/IsPrimitive', () => {
+  it('should equal false if T does not extend Primitive', () => {
+    expectTypeOf<TestSubject<Date>>().toEqualTypeOf<false>()
+  })
+
+  it('should equal true if T extends Primitive', () => {
+    expectTypeOf<TestSubject<Primitive>>().toEqualTypeOf<true>()
+  })
+})

src/types/if-primitive.ts

@@ -0,0 +1,20 @@
+/**
+ * @file Type Definitions - IfPrimitive
+ * @module tutils/types/IfPrimitive
+ */
+
+import type IsPrimitive from './is-primitive'
+
+/**
+ * Conditional type that resolves depending on whether or not `T` extends
+ * `Primitive`.
+ *
+ * @see {@linkcode IsPrimitive}
+ *
+ * @template T - Type to evaluate
+ * @template True - Type if `T` extends `Primitive`
+ * @template False - Type if `T` does not extend `Primitive`
+ */
+type IfPrimitive<T, True, False> = IsPrimitive<T> extends true ? True : False
+
+export type { IfPrimitive as default }

src/types/index.ts

@@ -33,6 +33,7 @@ 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 IfPrimitive } from './if-primitive'
 export type { default as IndexSignature } from './index-signature'
 export type { default as IsAny } from './is-any'
 export type { default as IsArray } from './is-array'
@@ -45,6 +46,7 @@ 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 IsPrimitive } from './is-primitive'
 export type { default as IsTuple } from './is-tuple'
 export type { default as Join } from './join'
 export type { default as JsonArray } from './json-array'

src/types/is-primitive.ts

@@ -0,0 +1,15 @@
+/**
+ * @file Type Definitions - IsPrimitive
+ * @module tutils/types/IsPrimitive
+ */
+
+import type Primitive from './primitive'
+
+/**
+ * Returns a boolean indicating if `T` extends {@linkcode Primitive}.
+ *
+ * @template T - Type to evaluate
+ */
+type IsPrimitive<T> = T extends Primitive ? true : false
+
+export type { IsPrimitive as default }