fix: 修复筛选没有结果时调用其他方法报错的BUG

Author: ahl5esoft

Diff for: README.md

@@ -9,7 +9,7 @@
                                                                                  \_/__/
 ```
 
-# Underscore.go [![GoDoc](https://godoc.org/github.com/ahl5esoft/golang-underscore?status.svg)](https://godoc.org/github.com/ahl5esoft/golang-underscore) [![Go Report Card](https://goreportcard.com/badge/github.com/ahl5esoft/golang-underscore)](https://goreportcard.com/report/github.com/ahl5esoft/golang-underscore) ![Version](https://img.shields.io/badge/version-2.4.0-green.svg)
+# Underscore.go [![GoDoc](https://godoc.org/github.com/ahl5esoft/golang-underscore?status.svg)](https://godoc.org/github.com/ahl5esoft/golang-underscore) [![Go Report Card](https://goreportcard.com/badge/github.com/ahl5esoft/golang-underscore)](https://goreportcard.com/report/github.com/ahl5esoft/golang-underscore) ![Version](https://img.shields.io/badge/version-2.4.1-green.svg)
 like <a href="http://underscorejs.org/">underscore.js</a> and C# LINQ, but for Go
 
 ## Installation

Diff for: any_test.go

@@ -14,6 +14,26 @@ func Benchmark_Any(b *testing.B) {
 	}
 }
 
+func Test_Any(t *testing.T) {
+	t.Run("source is empty slice", func(t *testing.T) {
+		arr := make([]testModel, 0)
+		res := Chain(arr).Any(func(r testModel, _ int) bool {
+			return r.ID == 0
+		})
+		assert.False(t, res)
+	})
+
+	t.Run("source is nil", func(t *testing.T) {
+		var arr []testModel
+		assert.Nil(t, arr)
+
+		res := Chain(arr).Any(func(r testModel, _ int) bool {
+			return r.ID == 0
+		})
+		assert.False(t, res)
+	})
+}
+
 func Test_Any_False(t *testing.T) {
 	ok := Chain([]testModel{
 		{ID: 1, Name: "one"},

Diff for: chain.go

@@ -1,6 +1,8 @@
 package underscore
 
-import "reflect"
+import (
+	"reflect"
+)
 
 // Chain is 创建枚举器
 func Chain(src interface{}) IEnumerable {
@@ -63,18 +65,20 @@ func chainFromValue(value reflect.Value) IEnumerable {
 			value.Len(),
 		)
 	default:
-		if iterator, ok := value.Interface().(IEnumerator); ok {
-			return enumerable{
-				Enumerator: func() IEnumerator {
-					return iterator
-				},
+		if value.IsValid() {
+			if iterator, ok := value.Interface().(IEnumerator); ok {
+				return enumerable{
+					Enumerator: func() IEnumerator {
+						return iterator
+					},
+				}
 			}
-		}
 
-		if value.Kind() == reflect.Ptr {
-			return chainFromValue(
-				value.Elem(),
-			)
+			if value.Kind() == reflect.Ptr {
+				return chainFromValue(
+					value.Elem(),
+				)
+			}
 		}
 
 		return enumerable{

Diff for: group_test.go

@@ -53,7 +53,7 @@ func Test_Group(t *testing.T) {
 		}).Value(resValue)
 		assert.EqualValues(
 			t,
-			resValue.Interface(),
+			resValue.Elem().Interface(),
 			map[string][]int{
 				"odd":  {1, 3, 5},
 				"even": {2, 4},

Diff for: map_test.go

@@ -1,7 +1,6 @@
 package underscore
 
 import (
-	"fmt"
 	"reflect"
 	"strconv"
 	"testing"
@@ -51,9 +50,6 @@ func Test_Map(t *testing.T) {
 			resValue.Elem().Interface(),
 			[]int{0, 1},
 		)
-		fmt.Println(resValue)
-
-		assert.True(t, false)
 	})
 }
 

Diff for: order_test.go

@@ -7,27 +7,45 @@ import (
 )
 
 func Test_Order(t *testing.T) {
-	arr := []testModel{
-		{ID: 2, Name: "two"},
-		{ID: 1, Name: "one"},
-		{ID: 3, Name: "three"},
-	}
-	var res []int
-	Chain(arr).Order(func(n testModel, _ int) int {
-		return n.ID
-	}).Map(func(r testModel, _ int) int {
-		return r.ID
-	}).Value(&res)
-	assert.Len(
-		t,
-		res,
-		len(arr),
-	)
-	assert.EqualValues(
-		t,
-		res,
-		[]int{1, 2, 3},
-	)
+	t.Run("ok", func(t *testing.T) {
+		arr := []testModel{
+			{ID: 2, Name: "two"},
+			{ID: 1, Name: "one"},
+			{ID: 3, Name: "three"},
+		}
+		var res []int
+		Chain(arr).Order(func(n testModel, _ int) int {
+			return n.ID
+		}).Map(func(r testModel, _ int) int {
+			return r.ID
+		}).Value(&res)
+		assert.Len(
+			t,
+			res,
+			len(arr),
+		)
+		assert.EqualValues(
+			t,
+			res,
+			[]int{1, 2, 3},
+		)
+	})
+
+	t.Run("chain", func(t *testing.T) {
+		arr := []testModel{
+			{ID: 2, Name: "two"},
+			{ID: 1, Name: "one"},
+			{ID: 3, Name: "three"},
+		}
+		var res []int
+		Chain(arr).Where(func(r testModel, _ int) bool {
+			return r.ID > 5
+		}).Order(func(r testModel, _ int) int {
+			return r.ID
+		}).Map(func(r testModel, _ int) int {
+			return r.ID
+		}).Value(&res)
+	})
 }
 
 func Test_OrderBy(t *testing.T) {