add safe slice

Author: goiste

slices/slices.go

@@ -109,6 +109,16 @@ func Intersect[T comparable](s []T, others ...[]T) []T {
 	return result
 }
 
+// SafeSlice
+// returns slice of slice via copy
+func SafeSlice[T any](s []T, from, to int) []T {
+	if to > len(s) {
+		to = len(s)
+	}
+
+	return Copy(s[from:to])
+}
+
 // Split
 // splits a given slice into parts by `partSize` elements
 func Split[T any](s []T, partSize int) [][]T {
@@ -117,19 +127,15 @@ func Split[T any](s []T, partSize int) [][]T {
 	}
 
 	if len(s) <= partSize {
-		return [][]T{s}
+		return [][]T{SafeSlice(s, 0, len(s))}
 	}
 
-	count := int(math.Ceil(float64(len(s)) / float64(partSize)))
-	result := make([][]T, count)
+	length := int(math.Ceil(float64(len(s)) / float64(partSize)))
 
-	for i := 0; i < count; i++ {
-		from := partSize * i
-		to := from + partSize
-		if to > len(s) {
-			to = len(s)
-		}
-		result[i] = s[from:to]
+	result := make([][]T, length)
+
+	for i := 0; i < length; i++ {
+		result[i] = SafeSlice(s, i*partSize, (i+1)*partSize)
 	}
 
 	return result

slices/slices_test.go

@@ -170,6 +170,18 @@ func TestIntersect(t *testing.T) {
 	}
 }
 
+func TestSafeSlice(t *testing.T) {
+	arr := Copy(stringSlice)
+
+	r := SafeSlice(arr, 1, 3)
+
+	arr[1] = "new"
+
+	if r[0] != "two" {
+		t.Errorf(errorFormat, r, []string{"two", "three"})
+	}
+}
+
 func TestSplit(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -382,7 +394,12 @@ func TestFormat(t *testing.T) {
 		exp    []string
 	}{
 		{name: "empty", input: []float64{}, exp: []string{}},
-		{name: "123", input: []float64{0.000001, 0.02, 0.300000003}, format: "%.2f", exp: []string{"0.00", "0.02", "0.30"}},
+		{
+			name:   "123",
+			input:  []float64{0.000001, 0.02, 0.300000003},
+			format: "%.2f",
+			exp:    []string{"0.00", "0.02", "0.30"},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {