perf(slice): compact method reduces the creation of one slice，add a few deprecation comments

maputil/map.go

@@ -308,7 +308,7 @@ func HasKey[K comparable, V any](m map[K]V, key K) bool {
 }
 
 // MapToStruct converts map to struct
-// Play: todo
+// Play: https://go.dev/play/p/2i04QYbFk9-
 func MapToStruct(m map[string]any, structObj any) error {
 	for k, v := range m {
 		err := setStructField(structObj, k, v)
@@ -388,6 +388,7 @@ func getFieldNameByJsonTag(structObj any, jsonTag string) string {
 }
 
 // ToSortedSlicesDefault converts a map to two slices sorted by key: one for the keys and another for the values.
+// Play: todo
 func ToSortedSlicesDefault[K constraints.Ordered, V any](m map[K]V) ([]K, []V) {
 	keys := make([]K, 0, len(m))
 
@@ -412,6 +413,7 @@ func ToSortedSlicesDefault[K constraints.Ordered, V any](m map[K]V) ([]K, []V) {
 
 // ToSortedSlicesWithComparator converts a map to two slices sorted by key and using a custom comparison function:
 // one for the keys and another for the values.
+// Play: todo
 func ToSortedSlicesWithComparator[K comparable, V any](m map[K]V, comparator func(a, b K) bool) ([]K, []V) {
 	keys := make([]K, 0, len(m))
 

slice/slice.go

@@ -97,30 +97,27 @@ func Chunk[T any](slice []T, size int) [][]T {
 func Compact[T comparable](slice []T) []T {
 	var zero T
 
-	result := make([]T, 0, len(slice))
-
+	i := 0
 	for _, v := range slice {
 		if v != zero {
-			result = append(result, v)
+			slice[i] = v
+			i++
 		}
 	}
-	return result[:len(result):len(result)]
+	return slice[:i]
 }
 
 // Concat creates a new slice concatenating slice with any additional slices.
 // Play: https://go.dev/play/p/gPt-q7zr5mk
-func Concat[T any](slice []T, slices ...[]T) []T {
-	totalLen := len(slice)
-
+func Concat[T any](slices ...[]T) []T {
+	totalLen := 0
 	for _, v := range slices {
 		totalLen += len(v)
 	}
-
 	result := make([]T, 0, totalLen)
 
-	result = append(result, slice...)
-	for _, s := range slices {
-		result = append(result, s...)
+	for _, v := range slices {
+		result = append(result, v...)
 	}
 
 	return result
@@ -695,10 +692,7 @@ func DropRight[T any](slice []T, n int) []T {
 	if n <= 0 {
 		return slice
 	}
-
-	result := make([]T, 0, size-n)
-
-	return append(result, slice[:size-n]...)
+	return slice[:size-n]
 }
 
 // DropWhile drop n elements from the start of a slice while predicate function returns true.
@@ -840,20 +834,11 @@ func UnionBy[T any, V comparable](predicate func(item T) V, slices ...[]T) []T {
 	return result
 }
 
+// Deprecated: use Concat instead.
 // Merge all given slices into one slice.
 // Play: https://go.dev/play/p/lbjFp784r9N
 func Merge[T any](slices ...[]T) []T {
-	totalLen := 0
-	for _, v := range slices {
-		totalLen += len(v)
-	}
-	result := make([]T, 0, totalLen)
-
-	for _, v := range slices {
-		result = append(result, v...)
-	}
-
-	return result
+	return Concat(slices...)
 }
 
 // Intersection creates a slice of unique elements that included by all slices.
@@ -1017,7 +1002,7 @@ func SortBy[T any](slice []T, less func(a, b T) bool) {
 	quickSortBy(slice, 0, len(slice)-1, less)
 }
 
-// SortByField return sorted slice by field
+// Deprecated: SortByField return sorted slice by field
 // slice element should be struct, field type should be int, uint, string, or bool
 // default sortType is ascending (asc), if descending order, set sortType to desc
 // This function is deprecated, use Sort and SortBy for replacement.

strutil/string.go

@@ -621,6 +621,8 @@ func HammingDistance(a, b string) (int, error) {
 // Concat uses the strings.Builder to concatenate the input strings.
 //   - `length` is the expected length of the concatenated string.
 //   - if you are unsure about the length of the string to be concatenated, please pass 0 or a negative number.
+//
+// Play: todo
 func Concat(length int, str ...string) string {
 	if len(str) == 0 {
 		return ""