Add sortBy/minBy/maxBy

common/cond.go

@@ -4,7 +4,10 @@ import (
 	"context"
 	"io"
 	"runtime"
+	"sort"
 	"unsafe"
+
+	"github.com/sagernet/sing/common/x/constraints"
 )
 
 func Any[T any](array []T, block func(it T) bool) bool {
@@ -161,6 +164,48 @@ func UniqBy[T any, C comparable](arr []T, block func(it T) C) []T {
 	return result
 }
 
+func SortBy[T any, C constraints.Ordered](arr []T, block func(it T) C) {
+	sort.Slice(arr, func(i, j int) bool {
+		return block(arr[i]) < block(arr[j])
+	})
+}
+
+func MinBy[T any, C constraints.Ordered](arr []T, block func(it T) C) T {
+	var min T
+	var minValue C
+	if len(arr) == 0 {
+		return min
+	}
+	min = arr[0]
+	for i := 1; i < len(arr); i++ {
+		item := arr[i]
+		value := block(item)
+		if value < minValue {
+			min = item
+			minValue = value
+		}
+	}
+	return min
+}
+
+func MaxBy[T any, C constraints.Ordered](arr []T, block func(it T) C) T {
+	var max T
+	var maxValue C
+	if len(arr) == 0 {
+		return max
+	}
+	max = arr[0]
+	for i := 1; i < len(arr); i++ {
+		item := arr[i]
+		value := block(item)
+		if value > maxValue {
+			max = item
+			maxValue = value
+		}
+	}
+	return max
+}
+
 func FilterIsInstance[T any, N any](arr []T, block func(it T) (N, bool)) []N {
 	var retArr []N
 	for _, it := range arr {