feat: add Shuffle for string

strutil/string.go

@@ -5,13 +5,18 @@ package strutil
 
 import (
 	"errors"
+	"math/rand"
 	"regexp"
 	"strings"
+	"time"
 	"unicode"
 	"unicode/utf8"
 	"unsafe"
 )
 
+// used in `Shuffle` function
+var rng = rand.New(rand.NewSource(int64(time.Now().UnixNano())))
+
 // CamelCase coverts string to camelCase string. Non letters and numbers will be ignored.
 // Play: https://go.dev/play/p/9eXP3tn2tUy
 func CamelCase(s string) string {
@@ -658,3 +663,16 @@ func Ellipsis(str string, length int) string {
 
 	return string(runes[:length]) + "..."
 }
+
+// Shuffle the order of characters of given string.
+// Play: todo
+func Shuffle(str string) string {
+	runes := []rune(str)
+
+	for i := len(runes) - 1; i > 0; i-- {
+		j := rng.Intn(i + 1)
+		runes[i], runes[j] = runes[j], runes[i]
+	}
+
+	return string(runes)
+}

strutil/string_test.go

@@ -728,3 +728,16 @@ func TestEllipsis(t *testing.T) {
 		assert.Equal(tt.want, Ellipsis(tt.input, tt.length))
 	}
 }
+
+func TestShuffle(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestShuffle")
+
+	assert.Equal("", Shuffle(""))
+	assert.Equal("a", Shuffle("a"))
+
+	str := "hello"
+	shuffledStr := Shuffle(str)
+	assert.Equal(5, len(shuffledStr))
+}