From 1ad990ce9d88f3e94f9129902968feec9c564da1 Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Mon, 24 Jan 2022 15:28:47 +0800
Subject: [PATCH] feat: add FindLast func

---
 slice/slice.go      | 28 ++++++++++++++++++++++++++++
 slice/slice_test.go | 16 +++++++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/slice/slice.go b/slice/slice.go
index 9f0b7fb..b8ada2f 100644
--- a/slice/slice.go
+++ b/slice/slice.go
@@ -367,6 +367,34 @@ func Find(slice, function interface{}) (interface{}, bool) {
 	return sv.Index(index).Interface(), true
 }
 
+// FindLast iterates over elements of slice from end to begin, returning the first one that passes a truth test on function.
+// The function signature should be func(index int, value interface{}) bool .
+func FindLast(slice, function interface{}) (interface{}, bool) {
+	sv := sliceValue(slice)
+	fn := functionValue(function)
+
+	elemType := sv.Type().Elem()
+	if checkSliceCallbackFuncSignature(fn, elemType, reflect.ValueOf(true).Type()) {
+		panic("function param should be of type func(int, " + elemType.String() + ")" + reflect.ValueOf(true).Type().String())
+	}
+
+	index := -1
+	for i := sv.Len() - 1; i >= 0; i-- {
+		flag := fn.Call([]reflect.Value{reflect.ValueOf(i), sv.Index(i)})[0]
+		if flag.Bool() {
+			index = i
+			break
+		}
+	}
+
+	if index == -1 {
+		var none interface{}
+		return none, false
+	}
+
+	return sv.Index(index).Interface(), true
+}
+
 // FlattenDeep flattens slice recursive
 func FlattenDeep(slice interface{}) interface{} {
 	sv := sliceValue(slice)
diff --git a/slice/slice_test.go b/slice/slice_test.go
index eec492d..3463ced 100644
--- a/slice/slice_test.go
+++ b/slice/slice_test.go
@@ -172,6 +172,20 @@ func TestFind(t *testing.T) {
 	assert.Equal(2, res)
 }
 
+func TestFindLast(t *testing.T) {
+	nums := []int{1, 2, 3, 4, 5}
+	even := func(i, num int) bool {
+		return num%2 == 0
+	}
+	res, ok := FindLast(nums, even)
+	if !ok {
+		t.Fatal("found nothing")
+	}
+
+	assert := internal.NewAssert(t, "TestFind")
+	assert.Equal(4, res)
+}
+
 func TestFindFoundNothing(t *testing.T) {
 	nums := []int{1, 1, 1, 1, 1, 1}
 	findFunc := func(i, num int) bool {
@@ -443,7 +457,7 @@ func TestDifferenceBy(t *testing.T) {
 	assert := internal.NewAssert(t, "TestDifferenceBy")
 
 	s1 := []int{1, 2, 3, 4, 5} //after add one: 2 3 4 5 6
-	s2 := []int{3, 4, 5} //after add one: 4 5 6
+	s2 := []int{3, 4, 5}       //after add one: 4 5 6
 	addOne := func(i int, v int) int {
 		return v + 1
 	}