release v2.3.2

update:
1. UnwarpOr
2. UnwarpOrDefault
3. ExtractPointer

add:
1. UnwrapOr
2. IsNil

README.md

@@ -4,7 +4,7 @@
 <br/>
 
 ![Go version](https://img.shields.io/badge/go-%3E%3Dv1.18-9cf)
-[![Release](https://img.shields.io/badge/release-2.3.1-green.svg)](https://github.com/duke-git/lancet/releases)
+[![Release](https://img.shields.io/badge/release-2.3.2-green.svg)](https://github.com/duke-git/lancet/releases)
 [![GoDoc](https://godoc.org/github.com/duke-git/lancet/v2?status.svg)](https://pkg.go.dev/github.com/duke-git/lancet/v2)
 [![Go Report Card](https://goreportcard.com/badge/github.com/duke-git/lancet/v2)](https://goreportcard.com/report/github.com/duke-git/lancet/v2)
 [![test](https://github.com/duke-git/lancet/actions/workflows/codecov.yml/badge.svg?branch=main&event=push)](https://github.com/duke-git/lancet/actions/workflows/codecov.yml)
@@ -901,6 +901,8 @@ import "github.com/duke-git/lancet/v2/maputil"
 -   **<big>HasKey</big>** : checks if map has key or not.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/maputil.md#HasKey)]
     [[play](https://go.dev/play/p/isZZHOsDhFc)]
+-   **<big>GetOrSet</big>** : returns value of the given key or set the given value value if not present.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/maputil.md#GetOrSet)]
 -   **<big>MapToStruct</big>** : converts map to struct.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/maputil.md#MapToStruct)]
     [[play](https://go.dev/play/p/7wYyVfX38Dp)]
@@ -1125,7 +1127,7 @@ import "github.com/duke-git/lancet/v2/pointer"
 -   **<big>Unwrap</big>** : return the value from the pointer.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/pointer.md#Unwrap)]
     [[play](https://go.dev/play/p/cgeu3g7cjWb)]
--   **<big>UnwarpOr</big>** : UnwarpOr returns the value from the pointer or fallback if the pointer is nil.
+-   **<big>UnwrapOr</big>** : UnwrapOr returns the value from the pointer or fallback if the pointer is nil.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/pointer.md#UnwrapOr)]
     [[play](https://go.dev/play/p/mmNaLC38W8C)]
 -   **<big>UnwarpOrDefault</big>** : UnwarpOrDefault returns the value from the pointer or the default value if the pointer is nil.
@@ -1414,6 +1416,8 @@ import "github.com/duke-git/lancet/v2/slice"
 -   **<big>UniqueBy</big>** : call iteratee func with every item of slice, then remove duplicated.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#UniqueBy)]
     [[play](https://go.dev/play/p/UR323iZLDpv)]
+-   **<big>UniqueByField</big>** : remove duplicate elements in struct slice by struct field.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#UniqueByField)]
 -   **<big>Union</big>** : creates a slice of unique elements, in order, from all given slices.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#Union)]
     [[play](https://go.dev/play/p/hfXV1iRIZOf)]

README_zh-CN.md

@@ -4,7 +4,7 @@
 <br/>
 
 ![Go version](https://img.shields.io/badge/go-%3E%3Dv1.18-9cf)
-[![Release](https://img.shields.io/badge/release-2.3.1-green.svg)](https://github.com/duke-git/lancet/releases)
+[![Release](https://img.shields.io/badge/release-2.3.2-green.svg)](https://github.com/duke-git/lancet/releases)
 [![GoDoc](https://godoc.org/github.com/duke-git/lancet/v2?status.svg)](https://pkg.go.dev/github.com/duke-git/lancet/v2)
 [![Go Report Card](https://goreportcard.com/badge/github.com/duke-git/lancet/v2)](https://goreportcard.com/report/github.com/duke-git/lancet/v2)
 [![test](https://github.com/duke-git/lancet/actions/workflows/codecov.yml/badge.svg?branch=main&event=push)](https://github.com/duke-git/lancet/actions/workflows/codecov.yml)
@@ -902,6 +902,8 @@ import "github.com/duke-git/lancet/v2/maputil"
     [[play](https://go.dev/play/p/N9qgYg_Ho6f)]
 -   **<big>HasKey</big>** : 检查 map 是否包含某个 key。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/maputil.md#HasKey)]
+-   **<big>GetOrSet</big>** : 返回给定键的值，如果不存在则设置该值。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/maputil.md#GetOrSet)]
     [[play](https://go.dev/play/p/isZZHOsDhFc)]
 -   **<big>MapToStruct</big>** : 将map转成struct。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/maputil.md#MapToStruct)]
@@ -1414,6 +1416,8 @@ import "github.com/duke-git/lancet/v2/slice"
 -   **<big>UniqueBy</big>** : 对切片的每个元素调用 iteratee 函数，然后删除重复元素。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#UniqueBy)]
     [[play](https://go.dev/play/p/UR323iZLDpv)]
+-   **<big>UniqueByField</big>** : 根据struct字段对struct切片去重复
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#UniqueByField)]
 -   **<big>Union</big>** : 合并多个切片。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#Union)]
     [[play](https://go.dev/play/p/hfXV1iRIZOf)]

docs/api/packages/maputil.md

@@ -55,6 +55,8 @@ import (
 -   [ConcurrentMap_GetAndDelete](#ConcurrentMap_GetAndDelete)
 -   [ConcurrentMap_Has](#ConcurrentMap_Has)
 -   [ConcurrentMap_Range](#ConcurrentMap_Range)
+-   [GetOrSet](#GetOrSet)
+
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -1483,3 +1485,41 @@ func main() {
     })
 }
 ```
+
+
+### <span id="GetOrSet">GetOrSet</span>
+
+<p>返回给定键的值，如果不存在则设置该值。</p>
+
+<b>函数签名:</b>
+
+```go
+func GetOrSet[K comparable, V any](m map[K]V, key K, value V) V
+```
+
+<b>示例:<span style="float:right;display:inline-block;"></span></b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+    }
+
+    result1 := maputil.GetOrSet(m, 1, "1")
+    result2 := maputil.GetOrSet(m, 2, "b")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // a
+    // b
+}
+```

docs/api/packages/pointer.md

@@ -25,8 +25,8 @@ import (
 -   [Of](#Of)
 -   [Unwrap](#Unwrap)
 -   [ExtractPointer](#ExtractPointer)
--   [UnwarpOr](#UnwarpOr)
--   [UnwarpOrDefault](#UnwarpOrDefault)
+-   [UnwrapOr](#UnwrapOr)
+-   [UnwrapOrDefault](#UnwrapOrDefault)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -136,14 +136,14 @@ func main() {
 }
 ```
 
-### <span id="UnwarpOr">UnwarpOr</span>
+### <span id="UnwrapOr">UnwrapOr</span>
 
 <p>返回指针的值，如果指针为零值，则返回fallback。</p>
 
 <b>函数签名:</b>
 
 ```go
-UnwarpOr[T any](p *T, fallback T) T
+UnwrapOr[T any](p *T, fallback T) T
 ```
 
 <b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/mmNaLC38W8C)</span></b>
@@ -163,10 +163,10 @@ func main() {
 	var c *int
 	var d *string
 
-	result1 := pointer.UnwarpOr(&a, 456)
-	result2 := pointer.UnwarpOr(&b, "abc")
-	result3 := pointer.UnwarpOr(c, 456)
-	result4 := pointer.UnwarpOr(d, "def")
+	result1 := pointer.UnwrapOr(&a, 456)
+	result2 := pointer.UnwrapOr(&b, "abc")
+	result3 := pointer.UnwrapOr(c, 456)
+	result4 := pointer.UnwrapOr(d, "def")
 
 	fmt.Println(result1)
 	fmt.Println(result2)
@@ -181,14 +181,14 @@ func main() {
 }
 ```
 
-### <span id="UnwarpOrDefault">UnwarpOrDefault</span>
+### <span id="UnwrapOrDefault">UnwrapOrDefault</span>
 
 <p>返回指针的值，如果指针为零值，则返回相应零值。</p>
 
 <b>函数签名:</b>
 
 ```go
-UnwarpOrDefault[T any](p *T) T
+UnwrapOrDefault[T any](p *T) T
 ```
 
 <b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/ZnGIHf8_o4E)</span></b>
@@ -208,10 +208,10 @@ func main() {
 	var c *int
 	var d *string
 
-	result1 := pointer.UnwarpOrDefault(&a)
-	result2 := pointer.UnwarpOrDefault(&b)
-	result3 := pointer.UnwarpOrDefault(c)
-	result4 := pointer.UnwarpOrDefault(d)
+	result1 := pointer.UnwrapOrDefault(&a)
+	result2 := pointer.UnwrapOrDefault(&b)
+	result3 := pointer.UnwrapOrDefault(c)
+	result4 := pointer.UnwrapOrDefault(d)
 
 	fmt.Println(result1)
 	fmt.Println(result2)

docs/api/packages/slice.md

@@ -86,6 +86,7 @@ import (
 -   [ToSlicePointer](#ToSlicePointer)
 -   [Unique](#Unique)
 -   [UniqueBy](#UniqueBy)
+-   [UniqueByField](#UniqueByField)
 -   [Union](#Union)
 -   [UnionBy](#UnionBy)
 -   [UpdateAt](#UpdateAt)
@@ -2312,6 +2313,47 @@ func main() {
 }
 ```
 
+### <span id="UniqueByField">UniqueByField</span>
+
+<p>根据struct字段对struct切片去重复。</p>
+
+<b>函数签名:</b>
+
+```go
+func UniqueByField[T any](slice []T, field string) ([]T, error)
+```
+
+<b>示例:<span style="float:right;display:inline-block;"></span></b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/slice"
+)
+
+func main() {
+    type User struct {
+        ID   int    `json:"id"`
+        Name string `json:"name"`
+    }
+
+    users := []User{
+        {ID: 1, Name: "a"},
+        {ID: 2, Name: "b"},
+        {ID: 1, Name: "c"},
+    }
+
+    result, err := slice.UniqueByField(users, "ID")
+    if err != nil {
+    }
+
+    fmt.Println(result)
+
+    // Output:
+    // [{1 a} {2 b}]
+}
+```
+
 ### <span id="Union">Union</span>
 
 <p>合并多个切片</p>
@@ -2594,14 +2636,14 @@ import (
 
 func main() {
     strs := []string{"a", "b", "a", "c", "d", "a"}
-	modifiedStrs, count := slice.SetToDefaultIf(strs, func(s string) bool { return "a" == s })
-	
+    modifiedStrs, count := slice.SetToDefaultIf(strs, func(s string) bool { return "a" == s })
+    
     fmt.Println(modifiedStrs)
-	fmt.Println(count)
-	
+    fmt.Println(count)
+    
     // Output:
-	// [ b  c d ]
-	// 3
+    // [ b  c d ]
+    // 3
 }
 ```
 
@@ -2657,11 +2699,11 @@ import (
 )
 
 func main() {
-  	nums := []int{1, 2, 3, 4, 5}
-	padded := slice.RightPadding(nums, 0, 3)
-	fmt.Println(padded)
-	// Output:
-	// [1 2 3 4 5 0 0 0]
+      nums := []int{1, 2, 3, 4, 5}
+    padded := slice.RightPadding(nums, 0, 3)
+    fmt.Println(padded)
+    // Output:
+    // [1 2 3 4 5 0 0 0]
 }
 ```
 
@@ -2684,10 +2726,10 @@ import (
 )
 
 func main() {
-  	nums := []int{1, 2, 3, 4, 5}
-	padded := slice.LeftPadding(nums, 0, 3)
-	fmt.Println(padded)
-	// Output:
-	// [0 0 0 1 2 3 4 5]
+      nums := []int{1, 2, 3, 4, 5}
+    padded := slice.LeftPadding(nums, 0, 3)
+    fmt.Println(padded)
+    // Output:
+    // [0 0 0 1 2 3 4 5]
 }
 ```

docs/en/api/packages/maputil.md

@@ -55,6 +55,7 @@ import (
 -   [ConcurrentMap_GetAndDelete](#ConcurrentMap_GetAndDelete)
 -   [ConcurrentMap_Has](#ConcurrentMap_Has)
 -   [ConcurrentMap_Range](#ConcurrentMap_Range)
+-   [GetOrSet](#GetOrSet)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -1501,3 +1502,40 @@ func main() {
     })
 }
 ```
+
+### <span id="GetOrSet">GetOrSet</span>
+
+<p>Returns value of the given key or set the given value value if not present.</p>
+
+<b>Signature:</b>
+
+```go
+func GetOrSet[K comparable, V any](m map[K]V, key K, value V) V
+```
+
+<b>Example:<span style="float:right;display:inline-block;"></span></b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+    }
+
+    result1 := maputil.GetOrSet(m, 1, "1")
+    result2 := maputil.GetOrSet(m, 2, "b")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // a
+    // b
+}
+```

docs/en/api/packages/pointer.md

@@ -24,8 +24,8 @@ import (
 
 -   [Of](#Of)
 -   [Unwrap](#Unwrap)
--   [UnwarpOr](#UnwarpOr)
--   [UnwarpOrDefault](#UnwarpOrDefault)
+-   [UnwrapOr](#UnwrapOr)
+-   [UnwrapOrDefault](#UnwrapOrDefault)
 -   [ExtractPointer](#ExtractPointer)
 
 <div STYLE="page-break-after: always;"></div>
@@ -103,13 +103,13 @@ func main() {
 ```
 
 
-### <span id="UnwarpOr">UnwarpOr</span>
+### <span id="UnwrapOr">UnwrapOr</span>
 
 <p>Returns the value from the pointer or fallback if the pointer is nil.</p>
 
 <b>Signature:</b>
 ```go
-UnwarpOr[T any](p *T, fallback T) T
+UnwrapOr[T any](p *T, fallback T) T
 ```
 
 <b>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/mmNaLC38W8C)</span></b>
@@ -129,10 +129,10 @@ func main() {
 	var c *int
 	var d *string
 
-	result1 := pointer.UnwarpOr(&a, 456)
-	result2 := pointer.UnwarpOr(&b, "abc")
-	result3 := pointer.UnwarpOr(c, 456)
-	result4 := pointer.UnwarpOr(d, "def")
+	result1 := pointer.UnwrapOr(&a, 456)
+	result2 := pointer.UnwrapOr(&b, "abc")
+	result3 := pointer.UnwrapOr(c, 456)
+	result4 := pointer.UnwrapOr(d, "def")
 
 	fmt.Println(result1)
 	fmt.Println(result2)
@@ -148,13 +148,13 @@ func main() {
 ```
 
 
-### <span id="UnwarpOrDefault">UnwarpOrDefault</span>
+### <span id="UnwrapOrDefault">UnwrapOrDefault</span>
 
 <p>Returns the value from the pointer or the default value if the pointer is nil.</p>
 
 <b>Signature:</b>
 ```go
-UnwarpOrDefault[T any](p *T) T
+UnwrapOrDefault[T any](p *T) T
 ```
 
 <b>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/ZnGIHf8_o4E)</span></b>
@@ -174,10 +174,10 @@ func main() {
 	var c *int
 	var d *string
 
-	result1 := pointer.UnwarpOrDefault(&a)
-	result2 := pointer.UnwarpOrDefault(&b)
-	result3 := pointer.UnwarpOrDefault(c)
-	result4 := pointer.UnwarpOrDefault(d)
+	result1 := pointer.UnwrapOrDefault(&a)
+	result2 := pointer.UnwrapOrDefault(&b)
+	result3 := pointer.UnwrapOrDefault(c)
+	result4 := pointer.UnwrapOrDefault(d)
 
 	fmt.Println(result1)
 	fmt.Println(result2)

docs/en/api/packages/slice.md

@@ -86,6 +86,7 @@ import (
 -   [ToSlicePointer](#ToSlicePointer)
 -   [Unique](#Unique)
 -   [UniqueBy](#UniqueBy)
+-   [UniqueByField](#UniqueByField)
 -   [Union](#Union)
 -   [UnionBy](#UnionBy)
 -   [UpdateAt](#UpdateAt)
@@ -2310,6 +2311,47 @@ func main() {
 }
 ```
 
+### <span id="UniqueByField">UniqueByField</span>
+
+<p>Remove duplicate elements in struct slice by struct field.</p>
+
+<b>Signature:</b>
+
+```go
+func UniqueByField[T any](slice []T, field string) ([]T, error)
+```
+
+<b>Example:<span style="float:right;display:inline-block;"></span></b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/slice"
+)
+
+func main() {
+    type User struct {
+        ID   int    `json:"id"`
+        Name string `json:"name"`
+    }
+
+    users := []User{
+        {ID: 1, Name: "a"},
+        {ID: 2, Name: "b"},
+        {ID: 1, Name: "c"},
+    }
+
+    result, err := slice.UniqueByField(users, "ID")
+    if err != nil {
+    }
+
+    fmt.Println(result)
+
+    // Output:
+    // [{1 a} {2 b}]
+}
+```
+
 ### <span id="Union">Union</span>
 
 <p>Creates a slice of unique values, in order, from all given slices. using == for equality comparisons.</p>

fileutil/file.go

@@ -119,58 +119,43 @@ func CreateDir(absPath string) error {
 // if dstPath exists, it will return an error.
 // Play: https://go.dev/play/p/YAyFTA_UuPb
 func CopyDir(srcPath string, dstPath string) error {
-	if !IsDir(srcPath) {
-		return errors.New("source path is not a directory")
-	}
-	var err error
-	srcPath, err = filepath.Abs(srcPath)
+	srcInfo, err := os.Stat(srcPath)
 	if err != nil {
-		return err
-	}
-	if IsExist(dstPath) {
-		return errors.New("destination path already exists")
-	}
-	dstPath, err = filepath.Abs(dstPath)
-	if err != nil {
-		return err
+		return fmt.Errorf("failed to get source directory info: %w", err)
 	}
 
-	// get srcPath's file info
-	srcFileInfo, err := os.Stat(srcPath)
-	if err != nil {
-		return err
+	if !srcInfo.IsDir() {
+		return fmt.Errorf("source path is not a directory: %s", srcPath)
 	}
 
-	// create dstPath with srcPath's mode
-	err = os.MkdirAll(dstPath, srcFileInfo.Mode())
+	err = os.MkdirAll(dstPath, 0755)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to create destination directory: %w", err)
 	}
 
-	err = filepath.Walk(srcPath, func(path string, info os.FileInfo, err error) error {
-		if srcPath == path {
-			return nil
-		}
-		curDstPath := filepath.Join(dstPath, filepath.Base(path))
-		if info.IsDir() {
-			err = CopyDir(path, curDstPath)
+	entries, err := os.ReadDir(srcPath)
+	if err != nil {
+		return fmt.Errorf("failed to read source directory: %w", err)
+	}
+
+	for _, entry := range entries {
+		srcDir := filepath.Join(srcPath, entry.Name())
+		dstDir := filepath.Join(dstPath, entry.Name())
+
+		if entry.IsDir() {
+			err := CopyDir(srcDir, dstDir)
 			if err != nil {
 				return err
 			}
 		} else {
-			err = CopyFile(path, curDstPath)
-			if err != nil {
-				return err
-			}
-			err = os.Chmod(curDstPath, info.Mode())
+			err := CopyFile(srcDir, dstDir)
 			if err != nil {
 				return err
 			}
 		}
-		return err
-	})
+	}
 
-	return err
+	return nil
 }
 
 // IsDir checks if the path is directory or not.

maputil/map.go

@@ -436,3 +436,15 @@ func ToSortedSlicesWithComparator[K comparable, V any](m map[K]V, comparator fun
 
 	return keys, sortedValues
 }
+
+// GetOrSet returns value of the given key or set the given value value if not present.
+// Play: todo
+func GetOrSet[K comparable, V any](m map[K]V, key K, value V) V {
+	if v, ok := m[key]; ok {
+		return v
+	}
+
+	m[key] = value
+
+	return value
+}

maputil/map_example_test.go

@@ -524,3 +524,19 @@ func ExampleToSortedSlicesWithComparator() {
 	// [3 2 1]
 	// [c b a]
 }
+
+func ExampleGetOrSet() {
+	m := map[int]string{
+		1: "a",
+	}
+
+	result1 := GetOrSet(m, 1, "1")
+	result2 := GetOrSet(m, 2, "b")
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+
+	// Output:
+	// a
+	// b
+}

maputil/map_test.go

@@ -691,3 +691,19 @@ func TestToSortedSlicesWithComparator(t *testing.T) {
 		})
 	}
 }
+
+func TestGetOrSet(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestGetOrSet")
+
+	m := map[int]string{
+		1: "a",
+	}
+
+	result1 := GetOrSet(m, 1, "1")
+	result2 := GetOrSet(m, 2, "b")
+
+	assert.Equal("a", result1)
+	assert.Equal("b", result2)
+}

pointer/pointer.go

@@ -11,17 +11,24 @@ import (
 // Of returns a pointer to the value `v`.
 // Play: https://go.dev/play/p/HFd70x4DrMj
 func Of[T any](v T) *T {
+	if IsNil(v) {
+		return nil
+	}
 	return &v
 }
 
 // Unwrap returns the value from the pointer.
-// Play: https://go.dev/play/p/cgeu3g7cjWb
+//
+//	Play: https://go.dev/play/p/cgeu3g7cjWb
+//	Deprecated: Please use UnwrapOr
 func Unwrap[T any](p *T) T {
 	return *p
 }
 
 // UnwarpOr returns the value from the pointer or fallback if the pointer is nil.
-// Play: https://go.dev/play/p/mmNaLC38W8C
+//
+//	Play: https://go.dev/play/p/mmNaLC38W8C
+//	Deprecated: Please use UnwrapOr
 func UnwarpOr[T any](p *T, fallback T) T {
 	if p == nil {
 		return fallback
@@ -30,7 +37,9 @@ func UnwarpOr[T any](p *T, fallback T) T {
 }
 
 // UnwarpOrDefault returns the value from the pointer or the default value if the pointer is nil.
-// Play: https://go.dev/play/p/ZnGIHf8_o4E
+//
+//	Play: https://go.dev/play/p/ZnGIHf8_o4E
+//	Deprecated: Please use UnwrapOr
 func UnwarpOrDefault[T any](p *T) T {
 	var v T
 
@@ -40,9 +49,24 @@ func UnwarpOrDefault[T any](p *T) T {
 	return *p
 }
 
+// UnwrapOr returns the value from the pointer or fallback if the pointer is nil.
+func UnwrapOr[T any](p *T, fallback ...T) T {
+	if !IsNil(p) {
+		return *p
+	}
+	if len(fallback) > 0 {
+		return fallback[0]
+	}
+	var t T
+	return t
+}
+
 // ExtractPointer returns the underlying value by the given interface type
 // Play: https://go.dev/play/p/D7HFjeWU2ZP
 func ExtractPointer(value any) any {
+	if IsNil(value) {
+		return value
+	}
 	t := reflect.TypeOf(value)
 	v := reflect.ValueOf(value)
 
@@ -56,3 +80,8 @@ func ExtractPointer(value any) any {
 
 	return nil
 }
+
+// IsNil returns true if the given interface is nil or the underlying value is nil.
+func IsNil(i interface{}) bool {
+	return i == nil || (reflect.ValueOf(i).Kind() == reflect.Ptr && reflect.ValueOf(i).IsNil())
+}

pointer/pointer_examples_test.go

@@ -90,3 +90,61 @@ func ExampleExtractPointer() {
 	// Output:
 	// 1
 }
+
+func ExampleIsNil() {
+	a := 1
+	b := &a
+	c := &b
+	d := &c
+	e := &d
+	var f *int
+
+	result1 := IsNil(a)
+	result2 := IsNil(b)
+	result3 := IsNil(c)
+	result4 := IsNil(d)
+	result5 := IsNil(e)
+	result6 := IsNil(f)
+	result7 := IsNil(nil)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+	fmt.Println(result4)
+	fmt.Println(result5)
+	fmt.Println(result6)
+	fmt.Println(result7)
+
+	// Output:
+	// false
+	// false
+	// false
+	// false
+	// false
+	// true
+	// true
+}
+
+func ExampleUnwrapOr() {
+	a := 123
+	b := "abc"
+
+	var c *int
+	var d *string
+
+	result1 := UnwrapOr(&a, 456)
+	result2 := UnwrapOr(&b, "efg")
+	result3 := UnwrapOr(c, 456)
+	result4 := UnwrapOr(d, "def")
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+	fmt.Println(result4)
+
+	// Output:
+	// 123
+	// abc
+	// 456
+	// def
+}

pointer/pointer_test.go

@@ -47,10 +47,10 @@ func TestUnwarpOr(t *testing.T) {
 	assert.Equal("def", UnwarpOr(d, "def"))
 }
 
-func TestUnwarpOrDefault(t *testing.T) {
+func TestUnwrapOrDefault(t *testing.T) {
 	t.Parallel()
 
-	assert := internal.NewAssert(t, "TestUnwarpOrDefault")
+	assert := internal.NewAssert(t, "TestUnwrapOrDefault")
 
 	a := 123
 	b := "abc"

slice/slice.go

@@ -796,6 +796,46 @@ func UniqueBy[T comparable](slice []T, iteratee func(item T) T) []T {
 	return Unique(result)
 }
 
+// UniqueByField remove duplicate elements in struct slice by struct field.
+// Play: todo
+func UniqueByField[T any](slice []T, field string) ([]T, error) {
+	seen := map[any]struct{}{}
+
+	var result []T
+	for _, item := range slice {
+		val, err := getField(item, field)
+		if err != nil {
+			return nil, fmt.Errorf("get field %s failed: %v", field, err)
+		}
+		if _, ok := seen[val]; !ok {
+			seen[val] = struct{}{}
+			result = append(result, item)
+		}
+	}
+
+	return result, nil
+}
+
+func getField[T any](item T, field string) (interface{}, error) {
+	v := reflect.ValueOf(item)
+	t := reflect.TypeOf(item)
+
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+		v = v.Elem()
+	}
+	if v.Kind() != reflect.Struct {
+		return nil, fmt.Errorf("data type %T not support, shuld be struct or pointer to struct", item)
+	}
+
+	f := v.FieldByName(field)
+	if !f.IsValid() {
+		return nil, fmt.Errorf("field name %s not found", field)
+	}
+
+	return v.FieldByName(field).Interface(), nil
+}
+
 // Union creates a slice of unique elements, in order, from all given slices.
 // Play: https://go.dev/play/p/hfXV1iRIZOf
 func Union[T comparable](slices ...[]T) []T {

slice/slice_example_test.go

@@ -780,6 +780,28 @@ func ExampleUniqueBy() {
 	// [1 2 0]
 }
 
+func ExampleUniqueByField() {
+	type User struct {
+		ID   int    `json:"id"`
+		Name string `json:"name"`
+	}
+
+	users := []User{
+		{ID: 1, Name: "a"},
+		{ID: 2, Name: "b"},
+		{ID: 1, Name: "c"},
+	}
+
+	result, err := UniqueByField(users, "ID")
+	if err != nil {
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// [{1 a} {2 b}]
+}
+
 func ExampleUnion() {
 	nums1 := []int{1, 3, 4, 6}
 	nums2 := []int{1, 2, 5, 6}

slice/slice_test.go

@@ -2,11 +2,12 @@ package slice
 
 import (
 	"fmt"
-	"github.com/duke-git/lancet/v2/internal"
 	"math"
 	"reflect"
 	"strconv"
 	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
 )
 
 func TestContain(t *testing.T) {
@@ -735,6 +736,33 @@ func TestUniqueBy(t *testing.T) {
 	assert.Equal([]int{1, 2, 3, 0}, actual)
 }
 
+func TestUniqueByField(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestUniqueByField")
+
+	type User struct {
+		ID   int    `json:"id"`
+		Name string `json:"name"`
+	}
+
+	users := []User{
+		{ID: 1, Name: "a"},
+		{ID: 2, Name: "b"},
+		{ID: 1, Name: "c"},
+	}
+
+	uniqueUsers, err := UniqueByField(users, "ID")
+	if err != nil {
+		t.Error(err)
+	}
+
+	assert.Equal([]User{
+		{ID: 1, Name: "a"},
+		{ID: 2, Name: "b"},
+	}, uniqueUsers)
+}
+
 func TestUnion(t *testing.T) {
 	t.Parallel()