fix(it.Mode): align behavior with lo.Mode and ensure consistent slice… (#711)

* fix(it.Mode): align behavior with lo.Mode and ensure consistent slice capacity

* replicating test section in main package

it/math.go

@@ -132,7 +132,7 @@ func MeanBy[T any, R constraints.Float | constraints.Integer](collection iter.Se
 // Long heterogeneous input sequences can cause excessive memory usage.
 // Play: https://go.dev/play/p/c_cmMMA5EhH
 func Mode[T constraints.Integer | constraints.Float](collection iter.Seq[T]) []T {
-	var mode []T
+	mode := make([]T, 0) 
 	maxFreq := 0
 	frequency := make(map[T]int)
 
@@ -142,11 +142,12 @@ func Mode[T constraints.Integer | constraints.Float](collection iter.Seq[T]) []T
 
 		if count > maxFreq {
 			maxFreq = count
-			mode = append(mode[:0], item)
+			mode = append(mode[:0], item) 
 		} else if count == maxFreq {
 			mode = append(mode, item)
 		}
 	}
 
-	return mode
+	return mode[:len(mode):len(mode)] 
 }
+

it/math_test.go

@@ -177,3 +177,15 @@ func TestMode(t *testing.T) {
 	is.Empty(result4)
 	is.Equal([]int{1, 2, 3, 4, 5, 6, 7, 8, 9}, result5)
 }
+
+func TestModeCapacityConsistency(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	arr := []int{1, 1, 2, 2, 3, 3, 3}
+
+	result := Mode(values(arr...))
+
+	is.Equal([]int{3}, result, "Mode should return correct mode value")
+	is.Equal(len(result), cap(result), "Mode slice capacity should match its length")
+}

math_test.go

@@ -191,3 +191,15 @@ func TestMode(t *testing.T) {
 	is.Empty(result4)
 	is.Equal([]int{1, 2, 3, 4, 5, 6, 7, 8, 9}, result5)
 }
+
+func TestModeCapacityConsistency(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	arr := []int{1, 1, 2, 2, 3, 3, 3}
+
+	result := Mode(arr)
+
+	is.Equal([]int{3}, result, "Mode should return correct mode value")
+	is.Equal(len(result), cap(result), "Mode slice capacity should match its length")
+}