From 0d11ce03a89d5f61e4fdcd2f41bd9e33b2140895 Mon Sep 17 00:00:00 2001
From: suplalalala <59185155+suplalalala@users.noreply.github.com>
Date: Sun, 16 Apr 2023 23:14:25 +0800
Subject: [PATCH] feature:  two evaluate operate func addtion in package stream
  (#3129)

Co-authored-by: Riven <Riven.chen@hairobotics.com>
---
 core/fx/stream.go      | 22 ++++++++++++
 core/fx/stream_test.go | 77 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

diff --git a/core/fx/stream.go b/core/fx/stream.go
index 44495f87..8a637164 100644
--- a/core/fx/stream.go
+++ b/core/fx/stream.go
@@ -540,3 +540,25 @@ func newOptions() *rxOptions {
 		workers: defaultWorkers,
 	}
 }
+
+// Max returns the maximum item from the underlying source.
+func (s Stream) Max(less LessFunc) any {
+	var maxItem any = nil
+	for item := range s.source {
+		if maxItem == nil || less(maxItem, item) {
+			maxItem = item
+		}
+	}
+	return maxItem
+}
+
+// Min returns the minimum item from the underlying source.
+func (s Stream) Min(less LessFunc) any {
+	var minItem any = nil
+	for item := range s.source {
+		if minItem == nil || !less(minItem, item) {
+			minItem = item
+		}
+	}
+	return minItem
+}
diff --git a/core/fx/stream_test.go b/core/fx/stream_test.go
index dd58d3e6..c6eaef56 100644
--- a/core/fx/stream_test.go
+++ b/core/fx/stream_test.go
@@ -503,6 +503,83 @@ func TestStream_Concat(t *testing.T) {
 	})
 }
 
+func TestStream_Max(t *testing.T) {
+	runCheckedTest(t, func(t *testing.T) {
+		tests := []struct {
+			name     string
+			elements []any
+			max      any
+		}{
+			{
+				name: "no elements with nil",
+			},
+			{
+				name:     "no elements",
+				elements: []any{},
+				max:      nil,
+			},
+			{
+				name:     "1 element",
+				elements: []any{1},
+				max:      1,
+			},
+			{
+				name:     "multiple elements",
+				elements: []any{1, 2, 9, 5, 8},
+				max:      9,
+			},
+		}
+
+		for _, test := range tests {
+			t.Run(test.name, func(t *testing.T) {
+				val := Just(test.elements...).Max(func(a, b any) bool {
+					return a.(int) < b.(int)
+				})
+				assetEqual(t, test.max, val)
+			})
+		}
+	})
+}
+
+func TestStream_Min(t *testing.T) {
+	runCheckedTest(t, func(t *testing.T) {
+		tests := []struct {
+			name     string
+			elements []any
+			min      any
+		}{
+			{
+				name: "no elements with nil",
+				min:  nil,
+			},
+			{
+				name:     "no elements",
+				elements: []any{},
+				min:      nil,
+			},
+			{
+				name:     "1 element",
+				elements: []any{1},
+				min:      1,
+			},
+			{
+				name:     "multiple elements",
+				elements: []any{-1, 1, 2, 9, 5, 8},
+				min:      -1,
+			},
+		}
+
+		for _, test := range tests {
+			t.Run(test.name, func(t *testing.T) {
+				val := Just(test.elements...).Min(func(a, b any) bool {
+					return a.(int) < b.(int)
+				})
+				assetEqual(t, test.min, val)
+			})
+		}
+	})
+}
+
 func BenchmarkParallelMapReduce(b *testing.B) {
 	b.ReportAllocs()