fix(min, max): Do not return undefined in non-empty arrays (#270)

* fix: improve min&max type

* Apply suggestions from code review

---------

Co-authored-by: Sojin Park <raon0211@gmail.com>

docs/ko/reference/compat/array/max.md

@@ -11,14 +11,16 @@
 ## 인터페이스
 
 ```typescript
-function max<T>(items: T[]): T;
+function max<T>(items: [T, ...T[]]): T;
+function max(): undefined;
+function max<T>(items?: T[]): T | undefined;
 ```
 
 ### 파라미터
 
 - `items` (`T[]`): 최댓값을 가지는 요소를 찾을 배열.
 
-### 반환 값 
+### 반환 값
 
 (`T`): 배열에서 최솟값을 가지는 요소. 배열이 비어 있다면 `undefined`를 반환해요.
 

docs/ko/reference/compat/array/min.md

@@ -11,7 +11,9 @@
 ## 인터페이스
 
 ```typescript
-function min<T>(items: T[]): T;
+function min<T>(items: [T, ...T[]]): T;
+function min(): undefined;
+function min<T>(items?: T[]): T | undefined;
 ```
 
 ### 파라미터

docs/reference/compat/array/max.md

@@ -11,7 +11,9 @@ If the list is empty, returns `undefined`.
 ## Signature
 
 ```typescript
-function max<T>(items: T[]): T;
+function max<T>(items: [T, ...T[]]): T;
+function max(): undefined;
+function max<T>(items?: T[]): T | undefined;
 ```
 
 ### Parameters

docs/reference/compat/array/min.md

@@ -11,7 +11,9 @@ If the list is empty, returns `undefined`.
 ## Signature
 
 ```typescript
-function min<T>(items: T[]): T;
+function min<T>(items: [T, ...T[]]): T;
+function min(): undefined;
+function min<T>(items?: T[]): T | undefined;
 ```
 
 ### Parameters

docs/zh_hans/reference/compat/array/max.md

@@ -11,7 +11,9 @@
 ## 签名
 
 ```typescript
-function max<T>(items: T[]): T;
+function max<T>(items: [T, ...T[]]): T;
+function max(): undefined;
+function max<T>(items?: T[]): T | undefined;
 ```
 
 ### 参数

docs/zh_hans/reference/compat/array/min.md

@@ -11,7 +11,9 @@
 ## 签名
 
 ```typescript
-function min<T>(items: T[]): T;
+function min<T>(items: [T, ...T[]]): T;
+function min(): undefined;
+function min<T>(items?: T[]): T | undefined;
 ```
 
 ### 参数

src/compat/math/max.ts

@@ -3,7 +3,7 @@
  *
  * @template T - The type of elements in the array.
  * @param {T[]} items The array of elements to search.
- * @returns {T} The element with the maximum value.
+ * @returns {T | undefined} The element with the maximum value.
  * @example
  * // Returns 9
  * max([3, 1, 4, 1, 5, 9])
@@ -12,7 +12,10 @@
  * // Returns 8
  * max([0, -3, 2, 8, 7])
  */
-export function max<T>(items: readonly T[] = []): T {
+export function max<T>(items: readonly [T, ...T[]]): T;
+export function max(): undefined;
+export function max<T>(items?: readonly T[]): T | undefined;
+export function max<T>(items: readonly T[] = []): T | undefined {
   let maxElement = items[0];
   let max = undefined;
 

src/compat/math/min.ts

@@ -3,7 +3,7 @@
  *
  * @template T - The type of elements in the array.
  * @param {T[]} items The array of elements to search.
- * @returns {T} The element with the minimum value.
+ * @returns {T | undefined} The element with the minimum value.
  * @example
  * // Returns 1
  * min([3, 1, 4, 1, 5, 9])
@@ -12,6 +12,9 @@
  * // Returns -3
  * min([0, -3, 2, 8, 7])
  */
+export function min<T>(items: readonly [T, ...T[]]): T;
+export function min(): undefined;
+export function min<T>(items?: readonly T[]): T | undefined;
 export function min<T>(items: readonly T[] = []): T {
   let minElement = items[0];
   let min = undefined;
@@ -24,4 +27,4 @@ export function min<T>(items: readonly T[] = []): T {
   }
 
   return minElement;
-}
+}