feat(chunk): filler can be a function

fjc0k · Apr 10, 2019 · 8451f6c · 8451f6c
1 parent 61046f2
commit 8451f6c
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/src/chunk.ts b/src/chunk.ts
@@ -1,3 +1,5 @@
+import { isFunction } from './isFunction'
+
 /**
  * 将 `array` 拆分成多个 `size` 长度的区块，并将它们组合成一个新数组返回。
  * 如果 `array` 无法等分，且设置了 `filler`，剩余的元素将被 `filler` 填充。
@@ -7,7 +9,7 @@
  * @param [filler] 填充物
  * @returns 拆分后的新数组
  */
-export function chunk<T, F = never>(array: T[], size: number, filler?: F): (T | F)[][] {
+export function chunk<T, F = never>(array: T[], size: number, filler?: ((index: number) => F) | F): (T | F)[][] {
   size = Math.max(size, 1)
   const result: (T | F)[][] = []
   const rows = Math.ceil(array.length / size)
@@ -16,8 +18,11 @@ export function chunk<T, F = never>(array: T[], size: number, filler?: F): (T |
   }
   const lastRow = result[rows - 1]
   if (arguments.length === 3 && lastRow.length < size) {
+    const fillerIsFunction = isFunction(filler)
     for (let i = 0, len = size - lastRow.length; i < len; i++) {
-      lastRow.push(filler)
+      lastRow.push(
+        fillerIsFunction ? (filler as any)(i) : filler,
+      )
     }
   }
   return result

diff --git a/test/index.test.ts b/test/index.test.ts
@@ -1581,7 +1581,10 @@ describe('chunk', () => {
     expect(vtils.chunk([1, 2], 0)).toEqual([[1], [2]])
     expect(vtils.chunk([1, 2], 1)).toEqual([[1], [2]])
     expect(vtils.chunk([1, 2, 3], 2)).toEqual([[1, 2], [3]])
+  })
+  test('filler ok', () => {
     expect(vtils.chunk([1, 2, 3], 2, 4)).toEqual([[1, 2], [3, 4]])
+    expect(vtils.chunk([1, 2, 3], 2, index => index)).toEqual([[1, 2], [3, 0]])
   })
 })