From afb021b4b57bc2a9e8702f37352681968be521b8 Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Wed, 8 Feb 2023 15:20:29 +0800
Subject: [PATCH] feat: add Max, Min for stream

---
 stream/stream.go      | 35 +++++++++++++++++++++++++++++++++++
 stream/stream_test.go | 22 ++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/stream/stream.go b/stream/stream.go
index b4f71d8..aa13787 100644
--- a/stream/stream.go
+++ b/stream/stream.go
@@ -323,6 +323,41 @@ func (s stream[T]) Sorted(less func(a, b T) bool) stream[T] {
 	return FromSlice(source)
 }
 
+// Max returns the maximum element of this stream according to the provided less function.
+// less: a > b
+func (s stream[T]) Max(less func(a, b T) bool) (T, bool) {
+	var max T
+
+	if len(s.source) == 0 {
+		return max, false
+	}
+
+	for i, v := range s.source {
+		if less(v, max) || i == 0 {
+			max = v
+		}
+	}
+	return max, true
+}
+
+// Min returns the minimum element of this stream according to the provided less function.
+// less: a < b
+func (s stream[T]) Min(less func(a, b T) bool) (T, bool) {
+	var min T
+
+	if len(s.source) == 0 {
+		return min, false
+	}
+
+	for i, v := range s.source {
+		if less(v, min) || i == 0 {
+			min = v
+		}
+	}
+
+	return min, true
+}
+
 // ToSlice return the elements in the stream.
 func (s stream[T]) ToSlice() []T {
 	return s.source
diff --git a/stream/stream_test.go b/stream/stream_test.go
index 0f62f7b..076d005 100644
--- a/stream/stream_test.go
+++ b/stream/stream_test.go
@@ -314,3 +314,25 @@ func TestStream_Sorted(t *testing.T) {
 	assert.Equal([]int{4, 2, 1, 3}, s.ToSlice())
 	assert.Equal([]int{1, 2, 3, 4}, s1.ToSlice())
 }
+
+func TestStream_Max(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStream_Max")
+
+	s := FromSlice([]int{4, 2, 1, 3})
+
+	max, ok := s.Max(func(a, b int) bool { return a > b })
+
+	assert.Equal(4, max)
+	assert.Equal(true, ok)
+}
+
+func TestStream_Min(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStream_Min")
+
+	s := FromSlice([]int{4, 2, 1, 3})
+
+	max, ok := s.Max(func(a, b int) bool { return a < b })
+
+	assert.Equal(1, max)
+	assert.Equal(true, ok)
+}