feat(sum): ensures that typing will work with things other than numbe…

…rs, objects

src/number/sum.ts

@@ -19,12 +19,12 @@
  * // => 2
  * ```
  */
-export function sum<T extends number>(array: readonly T[]): number
-export function sum<T extends object | boolean>(
+export function sum(array: readonly number[]): number
+export function sum<T>(
   array: readonly T[],
   fn: (item: T) => number,
 ): number
-export function sum<T extends object | number>(
+export function sum<T>(
   array: readonly any[],
   fn?: (item: T) => number,
 ): number {

tests/number/sum.test.ts

@@ -22,4 +22,14 @@ describe('sum', () => {
     const result = _.sum(list, x => (x ? 1 : 0))
     expect(result).toBe(3)
   })
+
+  test('gracefully handles matrix input', () => {
+    const list = [
+      [1, 2, 3],
+      [4, 5, 6],
+      [7, 8, 9],
+    ]
+    const result = _.sum(list, x => _.sum(x))
+    expect(result).toBe(45)
+  })
 })