feat(types): ExtractSetType, ExtractMapType, Promiseable 추가 (#94)

.changeset/fair-tips-smash.md

@@ -0,0 +1,5 @@
+---
+'@modern-kit/types': minor
+---
+
+feat(types): ExtractSetType, ExtractMapType, Promiseable 추가

packages/types/src/ExtractMapType/ExtractMapType.spec.ts

@@ -0,0 +1,15 @@
+import { ExtractMapType } from '.';
+
+describe('ExtractMapType', () => {
+  it('should infer the generic type of a Map', () => {
+    const key = 'foo' as 'foo' | 'bar';
+    const value = 1 as 1 | 2 | 3;
+
+    const testMap = new Map<typeof key, typeof value>();
+
+    type extractedMapType = ExtractMapType<typeof testMap>; // ["foo" | "bar", 1 | 2 | 3]
+
+    expectTypeOf(key).toEqualTypeOf<extractedMapType[0]>();
+    expectTypeOf(value).toEqualTypeOf<extractedMapType[1]>();
+  });
+});

packages/types/src/ExtractMapType/index.ts

@@ -0,0 +1,3 @@
+export type ExtractMapType<T> = T extends Map<infer K, infer V>
+  ? [K, V]
+  : never;

packages/types/src/ExtractSetType/ExtractSetType.spec.ts

@@ -0,0 +1,13 @@
+import { ExtractSetType } from '.';
+
+describe('ExtractSetType', () => {
+  it('should infer the generic type of a Set', () => {
+    const arr = [1, 2, 3, 4, 5] as const;
+    const testSet = new Set(arr);
+    const convertedTestArr = [...testSet];
+
+    type extractedSetType = ExtractSetType<typeof testSet>; // 1 | 2 | 3 | 4 | 5
+
+    expectTypeOf(convertedTestArr).toEqualTypeOf<extractedSetType[]>();
+  });
+});

packages/types/src/ExtractSetType/index.ts

@@ -0,0 +1 @@
+export type ExtractSetType<T> = T extends Set<infer U> ? U : never;

packages/types/src/Promiseable/Promiseable.spec.ts

@@ -0,0 +1,19 @@
+import { Promiseable } from '.';
+
+describe('Promiseable', () => {
+  it('should correctly handle and type-check a variable as either Promise<number> or number when assigned with Promiseable<number>', () => {
+    const promise = Promise.resolve(1) as Promiseable<number>;
+
+    expectTypeOf(promise).toEqualTypeOf<Promise<number> | number>();
+  });
+
+  it('should correctly distinguish between Promise<number> and number type at runtime when using Promiseable<number>', () => {
+    const promise = Promise.resolve(1) as Promiseable<number>;
+
+    if (promise instanceof Promise) {
+      expectTypeOf(promise).toEqualTypeOf<Promise<number>>();
+    } else {
+      expectTypeOf(promise).toEqualTypeOf<number>();
+    }
+  });
+});

packages/types/src/Promiseable/index.ts

@@ -0,0 +1 @@
+export type Promiseable<T> = T | Promise<T>;

packages/types/src/index.ts

@@ -1,7 +1,10 @@
 export * from './Arrayable';
 export * from './ExcludeNullish';
 export * from './ExtendOmittedProperties';
+export * from './ExtractMapType';
+export * from './ExtractSetType';
 export * from './IndexSignature';
 export * from './Nullable';
 export * from './ObjectEntries';
 export * from './ObjectKeys';
+export * from './Promiseable';