diff --git a/docs/array.md b/docs/array.md
index a58b2ae..2f12181 100644
--- a/docs/array.md
+++ b/docs/array.md
@@ -790,7 +790,7 @@ contains(['foo', 'bar'], 'baz'); // => false
 
 ```javascript
 // 相当于 [[[2]], [[4]], [[6]], [[8]]].flat()
-[1, 2, 3, 4].flatMap(x => [[x * x]])
+[1, 2, 3, 4].flatMap(x => [[x * 2]])
 // [[2], [4], [6], [8]]
 ```