feat: add AddIfNotExistBy function for set

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-2.1.9-green.svg)](https://github.com/duke-git/lancet/releases)
+[![Release](https://img.shields.io/badge/release-2.1.10-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)
@@ -19,7 +19,7 @@
     Lancet is a comprehensive, efficient, and reusable util function library of go. Inspired by the java apache common package and lodash.js.
 </p>
 
-English | [简体中文](./README_zh-CN.md)
+English | [简体中文](./README_zh-CN.md) | [Website](https://uvdream.github.io/lancet-docs/en/)
 
 ## Feature
 
@@ -38,7 +38,7 @@ English | [简体中文](./README_zh-CN.md)
 go get github.com/duke-git/lancet/v2 // will install latest version of v2.x.x
 ```
 
-2. <b>For users who use version below go1.18, you should install v1.x.x. now latest v1 is v1.3.3. </b>
+2. <b>For users who use version below go1.18, you should install v1.x.x. now latest v1 is v1.3.4. </b>
 
 ```go
 go get github.com/duke-git/lancet@v1.3.3 // below go1.18, install latest version of v1.x.x

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-2.1.9-green.svg)](https://github.com/duke-git/lancet/releases)
+[![Release](https://img.shields.io/badge/release-2.1.10-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)
@@ -18,7 +18,7 @@
     lancet（柳叶刀）是一个全面、高效、可复用的go语言工具函数库。 lancet受到了java apache common包和lodash.js的启发。
 </p>
 
-简体中文 | [English](./README.md)
+简体中文 | [English](./README.md) | [文档](https://uvdream.github.io/lancet-docs)
 
 ## 特性
 
@@ -37,7 +37,7 @@
 go get github.com/duke-git/lancet/v2 //安装v2最新版本v2.x.x
 ```
 
-2. <b>使用 go1.18 以下版本的用户，必须安装 v1.x.x。目前最新的 v1 版本是 v1.3.3。</b>
+2. <b>使用 go1.18 以下版本的用户，必须安装 v1.x.x。目前最新的 v1 版本是 v1.3.4。</b>
 
 ```go
 go get github.com/duke-git/lancet@v1.3.3 // 使用go1.18以下版本, 必须安装v1.x.x版本

SECURITY.md

@@ -0,0 +1,15 @@
+# Security Policy
+
+## Supported Versions
+Here is the lancet version and compatibility with go language version.
+
+| Version | Supported         |
+| ------- | ------------------|
+| 2.x.x   | +go v1.18         |
+| 1.x.x   | +go v1.12         |
+
+
+## Reporting a Vulnerability
+
+For now, there is no public website to report a vulnerability, If you find security issue in lancet, you can send it to me via my email `lanliddd.2007@163.com`.
+we can discuss it. I am appreciate if someone can create a public page for reporting vulnerability.

datastructure/set/set.go

@@ -4,19 +4,47 @@ package datastructure
 type Set[T comparable] map[T]struct{}
 
 // NewSet return a instance of set
-func NewSet[T comparable](values ...T) Set[T] {
+func NewSet[T comparable](items ...T) Set[T] {
 	set := make(Set[T])
-	set.Add(values...)
+	set.Add(items...)
 	return set
 }
 
-// Add value to set
+// Add items to set
-func (s Set[T]) Add(values ...T) {
+func (s Set[T]) Add(items ...T) {
-	for _, v := range values {
+	for _, v := range items {
 		s[v] = struct{}{}
 	}
 }
 
+// AddIfNotExist checks if item exists in the set,
+// it adds the item to set and returns true if it does not exist in the set,
+// or else it does nothing and returns false.
+func (s Set[T]) AddIfNotExist(value T) bool {
+	if !s.Contain(value) {
+		if _, ok := s[value]; !ok {
+			s[value] = struct{}{}
+			return true
+		}
+	}
+	return false
+}
+
+// AddIfNotExistBy checks if item exists in the set and pass the `checker` function
+// it adds the item to set and returns true if it does not exists in the set and
+// function `checker` returns true, or else it does nothing and returns false.
+func (s Set[T]) AddIfNotExistBy(item T, checker func(element T) bool) bool {
+	if !s.Contain(item) {
+		if checker(item) {
+			if _, ok := s[item]; !ok {
+				s[item] = struct{}{}
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // Contain checks if set contains value or not
 func (s Set[T]) Contain(value T) bool {
 	_, ok := s[value]
@@ -41,9 +69,9 @@ func (s Set[T]) Clone() Set[T] {
 	return set
 }
 
-// Delete value of set
+// Delete item of set
-func (s Set[T]) Delete(values ...T) {
+func (s Set[T]) Delete(items ...T) {
-	for _, v := range values {
+	for _, v := range items {
 		delete(s, v)
 	}
 }
@@ -76,13 +104,13 @@ func (s Set[T]) Size() int {
 
 // Values return all values of set
 func (s Set[T]) Values() []T {
-	values := make([]T, 0, 0)
+	result := make([]T, 0, len(s))
 
 	s.Iterate(func(value T) {
-		values = append(values, value)
+		result = append(result, value)
 	})
 
-	return values
+	return result
 }
 
 // Union creates a new set contain all element of set s and other

datastructure/set/set_test.go

@@ -17,6 +17,38 @@ func TestSet_Add(t *testing.T) {
 	assert.Equal(true, set.Equal(expected))
 }
 
+func TestSet_AddIfNotExist(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSet_AddIfNotExist")
+
+	set := NewSet[int]()
+	set.Add(1, 2, 3)
+
+	assert.Equal(false, set.AddIfNotExist(1))
+	assert.Equal(true, set.AddIfNotExist(4))
+	assert.Equal(NewSet(1, 2, 3, 4), set)
+}
+
+func TestSet_AddIfNotExistBy(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSet_AddIfNotExistBy")
+
+	set := NewSet[int]()
+	set.Add(1, 2)
+
+	ok := set.AddIfNotExistBy(3, func(val int) bool {
+		return val%2 != 0
+	})
+
+	notOk := set.AddIfNotExistBy(4, func(val int) bool {
+		return val%2 != 0
+	})
+
+	assert.Equal(true, ok)
+	assert.Equal(false, notOk)
+
+	assert.Equal(true, set.Contain(3))
+	assert.Equal(false, set.Contain(4))
+}
+
 func TestSet_Contain(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSet_Contain")
 

docs/algorithm.md

@@ -21,6 +21,7 @@ import (
 <div STYLE="page-break-after: always;"></div>
 
 ## Index
+
 - [BubbleSort](#BubbleSort)
 - [InsertionSort](#InsertionSort)
 - [SelectionSort](#SelectionSort)
@@ -31,7 +32,6 @@ import (
 - [CountSort](#CountSort)
 - [BinarySearch](#BinarySearch)
 - [BinaryIterativeSearch](#BinaryIterativeSearch)
-
 - [LinearSearch](#LinearSearch)
 - [LRUCache](#LRUCache)
 

docs/algorithm_zh-CN.md

@@ -29,7 +29,6 @@ import (
 - [QuickSort](#QuickSort)
 - [HeapSort](#HeapSort)
 - [MergeSort](#MergeSort)
-
 - [CountSort](#CountSort)
 - [BinarySearch](#BinarySearch)
 - [BinaryIterativeSearch](#BinaryIterativeSearch)

docs/convertor.md

@@ -25,7 +25,6 @@ import (
 - [ToBytes](#ToBytes)
 - [ToChar](#ToChar)
 - [ToChannel](#ToChannel)
-
 - [ToFloat](#ToFloat)
 - [ToInt](#ToInt)
 - [ToJson](#ToJson)

docs/convertor_zh-CN.md

@@ -27,7 +27,6 @@ import (
 - [ToBytes](#ToBytes)
 - [ToChar](#ToChar)
 - [ToChannel](#ToChannel)
-
 - [ToFloat](#ToFloat)
 - [ToInt](#ToInt)
 - [ToJson](#ToJson)

docs/cryptor.md

@@ -47,7 +47,6 @@ import (
 - [HmacSha1](#HmacSha1)
 - [HmacSha256](#HmacSha256)
 - [HmacSha512](#HmacSha512)
-
 - [Md5String](#Md5String)
 - [Md5File](#Md5File)
 - [Sha1](#Sha1)

docs/cryptor_zh-CN.md

@@ -33,7 +33,6 @@ import (
 - [AesOfbDecrypt](#AesOfbDecrypt)
 - [Base64StdEncode](#Base64StdEncode)
 - [Base64StdDecode](#Base64StdDecode)
-
 - [DesEcbEncrypt](#DesEcbEncrypt)
 - [DesEcbDecrypt](#DesEcbDecrypt)
 - [DesCbcEncrypt](#DesCbcEncrypt)
@@ -43,7 +42,6 @@ import (
 - [DesCfbDecrypt](#DesCfbDecrypt)
 - [DesOfbEncrypt](#DesOfbEncrypt)
 - [DesOfbDecrypt](#DesOfbDecrypt)
-
 - [HmacMd5](#HmacMd5)
 - [HmacSha1](#HmacSha1)
 - [HmacSha256](#HmacSha256)

docs/datastructure/set.md

@@ -34,7 +34,6 @@ import (
 - [IsEmpty](#IsEmpty)
 - [Union](#Union)
 - [Intersection](#Intersection)
-
 - [SymmetricDifference](#SymmetricDifference)
 - [Minus](#Minus)
 

docs/datastructure/set_zh-CN.md

@@ -34,7 +34,6 @@ import (
 - [IsEmpty](#IsEmpty)
 - [Union](#Union)
 - [Intersection](#Intersection)
-
 - [SymmetricDifference](#SymmetricDifference)
 - [Minus](#Minus)
 

docs/datastructure/tree.md

@@ -29,7 +29,6 @@ import (
 - [PreOrderTraverse](#BSTree_PreOrderTraverse)
 - [InOrderTraverse](#BSTree_InOrderTraverse)
 - [PostOrderTraverse](#BSTree_PostOrderTraverse)
-  
 - [LevelOrderTraverse](#BSTree_LevelOrderTraverse)
 - [Depth](#BSTree_Depth)
 - [HasSubTree](#BSTree_HasSubTree)

docs/datastructure/tree_zh-CN.md

@@ -29,7 +29,6 @@ import (
 - [PreOrderTraverse](#BSTree_PreOrderTraverse)
 - [InOrderTraverse](#BSTree_InOrderTraverse)
 - [PostOrderTraverse](#BSTree_PostOrderTraverse)
-  
 - [LevelOrderTraverse](#BSTree_LevelOrderTraverse)
 - [Depth](#BSTree_Depth)
 - [HasSubTree](#BSTree_HasSubTree)

docs/datetime.md

@@ -42,7 +42,6 @@ import (
 - [GetNightTimestamp](#GetNightTimestamp)
 - [FormatTimeToStr](#FormatTimeToStr)
 - [FormatStrToTime](#FormatStrToTime)
-
 - [NewUnixNow](#NewUnixNow)
 - [NewUnix](#NewUnix)
 - [NewFormat](#NewFormat)

docs/datetime_zh-CN.md

@@ -41,7 +41,6 @@ import (
 - [GetNightTimestamp](#GetNightTimestamp)
 - [FormatTimeToStr](#FormatTimeToStr)
 - [FormatStrToTime](#FormatStrToTime)
-
 - [NewUnixNow](#NewUnixNow)
 - [NewUnix](#NewUnix)
 - [NewFormat](#NewFormat)

docs/fileutil.md

@@ -28,7 +28,6 @@ import (
 - [IsExist](#IsExist)
 - [IsLink](#IsLink)
 - [IsDir](#IsDir)
-
 - [ListFileNames](#ListFileNames)
 - [RemoveFile](#RemoveFile)
 - [ReadFileToString](#ReadFileToString)

docs/fileutil_zh-CN.md

@@ -28,7 +28,6 @@ import (
 - [IsExist](#IsExist)
 - [IsLink](#IsLink)
 - [IsDir](#IsDir)
-
 - [ListFileNames](#ListFileNames)
 - [RemoveFile](#RemoveFile)
 - [ReadFileToString](#ReadFileToString)

docs/mathutil.md

@@ -28,7 +28,6 @@ import (
 - [MaxBy](#MaxBy)
 - [Min](#Min)
 - [MinBy](#MaxBy)
-
 - [Percent](#Percent)
 - [RoundToFloat](#RoundToFloat)
 - [RoundToString](#RoundToString)

docs/mathutil_zh-CN.md

@@ -28,7 +28,6 @@ import (
 - [MaxBy](#MaxBy)
 - [Min](#Min)
 - [MinBy](#MaxBy)
-  
 - [Percent](#Percent)
 - [RoundToFloat](#RoundToFloat)
 - [RoundToString](#RoundToString)

docs/netutil.md

@@ -25,7 +25,6 @@ import (
 ## Index
 - [ConvertMapToQueryString](#ConvertMapToQueryString)
 - [EncodeUrl](#EncodeUrl)
-  
 - [GetInternalIp](#GetInternalIp)
 - [GetIps](#GetIps)
 - [GetMacAddrs](#GetMacAddrs)
@@ -38,7 +37,6 @@ import (
 - [SendRequest](#SendRequest)
 - [DecodeResponse](#DecodeResponse)
 - [StructToUrlValues](#StructToUrlValues)
-
 - [HttpGet<sup>Deprecated</sup>](#HttpGet)
 - [HttpDelete<sup>Deprecated</sup>](#HttpDelete)
 - [HttpPost<sup>Deprecated</sup>](#HttpPost)

docs/netutil_zh-CN.md

@@ -30,7 +30,6 @@ import (
 - [GetMacAddrs](#GetMacAddrs)
 - [GetPublicIpInfo](#GetPublicIpInfo)
 - [GetRequestPublicIp](#GetRequestPublicIp)
-
 - [IsPublicIP](#IsPublicIP)
 - [IsInternalIP](#IsInternalIP)
 - [HttpRequest](#HttpRequest)
@@ -38,13 +37,11 @@ import (
 - [SendRequest](#SendRequest)
 - [DecodeResponse](#DecodeResponse)
 - [StructToUrlValues](#StructToUrlValues)
-
 - [HttpGet<sup>Deprecated</sup>](#HttpGet)
 - [HttpDelete<sup>Deprecated</sup>](#HttpDelete)
 - [HttpPost<sup>Deprecated</sup>](#HttpPost)
 - [HttpPut<sup>Deprecated</sup>](#HttpPut)
 - [HttpPatch<sup>Deprecated</sup>](#HttpPatch)
-
 - [ParseHttpResponse](#ParseHttpResponse)
 
 <div STYLE="page-break-after: always;"></div>

docs/random.md

@@ -26,7 +26,6 @@ import (
 -   [RandInt](#RandInt)
 -   [RandString](#RandString)
 -   [RandUpper](#RandUpper)
-
 -   [RandLower](#RandLower)
 -   [RandNumeral](#RandNumeral)
 -   [RandNumeralOrLetter](#RandNumeralOrLetter)

docs/random_zh-CN.md

@@ -26,7 +26,6 @@ import (
 -   [RandInt](#RandInt)
 -   [RandString](#RandString)
 -   [RandUpper](#RandUpper)
-
 -   [RandLower](#RandLower)
 -   [RandNumeral](#RandNumeral)
 -   [RandNumeralOrLetter](#RandNumeralOrLetter)

docs/slice.md

@@ -172,8 +172,8 @@ import (
 
 func main() {
 	arr := []string{"a", "b", "c", "d", "e"}
-	res := slice.Chunk(InterfaceSlice(arr), 3)
+	res := slice.Chunk((arr), 3)
-	fmt.Println(res) //[][]any{{"a", "b", "c"}, {"d", "e"}}
+	fmt.Println(res) //[][]string{{"a", "b", "c"}, {"d", "e"}}
 }
 ```
 

docs/slice_zh-CN.md

@@ -20,8 +20,10 @@ import (
 
 <div STYLE="page-break-after: always;"></div>
 
+
 ## 目录
 
+
 -   [AppendIfAbsent](#AppendIfAbsent)
 -   [Contain](#Contain)
 -   [ContainSubSlice](#ContainSubSlice)
@@ -46,7 +48,6 @@ import (
 -   [GroupBy](#GroupBy)
 -   [GroupWith](#GroupWith)
 -   [IntSlice](#IntSlice)
-
 -   [InterfaceSlice](#InterfaceSlice)
 -   [Intersection](#Intersection)
 -   [InsertAt](#InsertAt)
@@ -72,6 +73,7 @@ import (
 -   [Without](#Without)
 -   [KeyBy](#KeyBy)
 
+
 <div STYLE="page-break-after: always;"></div>
 
 ## 文档
@@ -172,8 +174,8 @@ import (
 
 func main() {
 	arr := []string{"a", "b", "c", "d", "e"}
-	res := slice.Chunk(InterfaceSlice(arr), 3)
+	res := slice.Chunk(arr, 3)
-	fmt.Println(res) //[][]any{{"a", "b", "c"}, {"d", "e"}}
+	fmt.Println(res) //[][]string{{"a", "b", "c"}, {"d", "e"}}
 }
 ```
 

docs/strutil.md

@@ -36,7 +36,6 @@ import (
 - [SnakeCase](#SnakeCase)
 - [SplitEx](#SplitEx)
 - [Wrap](#Wrap)
-  
 - [Unwrap](#Unwrap)
   
 

docs/strutil_zh-CN.md

@@ -36,7 +36,6 @@ import (
 - [SnakeCase](#SnakeCase)
 - [SplitEx](#SplitEx)
 - [Wrap](#Wrap)
-  
 - [Unwrap](#Unwrap)
   
 

docs/validator.md

@@ -34,7 +34,6 @@ import (
 - [IsCreditCard](#IsCreditCard)
 - [IsDns](#IsDns)
 - [IsEmail](#IsEmail)
-  
 - [IsEmptyString](#IsEmptyString)
 - [IsFloatStr](#IsFloatStr)
 - [IsNumberStr](#IsNumberStr)

docs/validator_zh-CN.md

@@ -34,7 +34,6 @@ import (
 - [IsCreditCard](#IsCreditCard)
 - [IsDns](#IsDns)
 - [IsEmail](#IsEmail)
-  
 - [IsEmptyString](#IsEmptyString)
 - [IsFloatStr](#IsFloatStr)
 - [IsNumberStr](#IsNumberStr)

fileutil/file.go

@@ -8,6 +8,7 @@ import (
 	"archive/zip"
 	"bufio"
 	"errors"
+	"fmt"
 	"io"
 	"io/fs"
 	"io/ioutil"
@@ -213,6 +214,7 @@ func Zip(fpath string, destPath string) error {
 
 // UnZip unzip the file and save it to destPath
 func UnZip(zipFile string, destPath string) error {
+
 	zipReader, err := zip.OpenReader(zipFile)
 	if err != nil {
 		return err
@@ -220,7 +222,12 @@ func UnZip(zipFile string, destPath string) error {
 	defer zipReader.Close()
 
 	for _, f := range zipReader.File {
-		path := filepath.Join(destPath, f.Name)
+		//issue#62: fix ZipSlip bug
+		path, err := safeFilepathJoin(destPath, f.Name)
+		if err != nil {
+			return err
+		}
+
 		if f.FileInfo().IsDir() {
 			os.MkdirAll(path, os.ModePerm)
 		} else {
@@ -249,6 +256,17 @@ func UnZip(zipFile string, destPath string) error {
 	return nil
 }
 
+func safeFilepathJoin(path1, path2 string) (string, error) {
+	relPath, err := filepath.Rel(".", path2)
+	if err != nil || strings.HasPrefix(relPath, "..") {
+		return "", fmt.Errorf("(zipslip) filepath is unsafe %q: %v", path2, err)
+	}
+	if path1 == "" {
+		path1 = "."
+	}
+	return filepath.Join(path1, filepath.Join("/", relPath)), nil
+}
+
 // IsLink checks if a file is symbol link or not
 func IsLink(path string) bool {
 	fi, err := os.Lstat(path)

iterator/iterator.go

@@ -0,0 +1,174 @@
+// Copyright 2022 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+// Package iterator provides a way to iterate over values stored in containers.
+// note:
+// 1. Full feature iterator is complicated, this pacakge is just a experiment to explore how iterators could work in Go.
+// 2. The functionality of this package is very simple and limited, may not meet the actual dev needs.
+// 3. It is currently under development, unstable, and will not be completed for some time in the future.
+// So, based on above factors, you may not use it in production. but, anyone is welcome to improve it.
+// Hope that Go can support iterator in future. see https://github.com/golang/go/discussions/54245 and https://github.com/golang/go/discussions/56413
+package iterator
+
+import "github.com/duke-git/lancet/v2/lancetconstraints"
+
+// Iterator supports iterating over a sequence of values of type `E`.
+type Iterator[T any] interface {
+	// Next checks if there is a next value in the iteration or not
+	HasNext() bool
+	// Next returns the next value in the iteration if there is one,
+	// and reports whether the returned value is valid.
+	// Once Next returns ok==false, the iteration is over,
+	// and all subsequent calls will return ok==false.
+	Next() (item T, ok bool)
+}
+
+// StopIterator is an  interface for stopping Iterator.
+type StopIterator[T any] interface {
+	Iterator[T]
+
+	// Stop indicates that the iterator will no longer be used.
+	// After a call to Stop, future calls to Next may panic.
+	// Stop may be called multiple times;
+	// all calls after the first will have no effect.
+	Stop()
+}
+
+// DeleteIter is an Iter that implements a Delete method.
+type DeleteIterator[T any] interface {
+	Iterator[T]
+
+	// Delete deletes the current iterator element;
+	// that is, the one returned by the last call to Next.
+	// Delete should panic if called before Next or after
+	// Next returns false.
+	Delete()
+}
+
+// SetIterator is an Iter that implements a Set method.
+type SetIterator[T any] interface {
+	Iterator[T]
+
+	// Set replaces the current iterator element with v.
+	// Set should panic if called before Next or after
+	// Next returns false.
+	Set(v T)
+}
+
+// PrevIterator is an iterator with a Prev method.
+type PrevIterator[T any] interface {
+	Iterator[T]
+
+	// Prev moves the iterator to the previous position.
+	// After calling Prev, Next will return the value at
+	// that position in the container. For example, after
+	//   it.Next() returning (v, true)
+	//   it.Prev()
+	// another call to it.Next will again return (v, true).
+	// Calling Prev before calling Next may panic.
+	// Calling Prev after Next returns false will move
+	// to the last element, or, if there are no elements,
+	// to the iterator's initial state.
+	Prev()
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Functions that create an Iterator from some other type.                                       //
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// FromSlice returns an iterator over a slice of data.
+func FromSlice[T any](slice []T) Iterator[T] {
+	return &sliceIterator[T]{slice: slice, index: -1}
+}
+
+func ToSlice[T any](iter Iterator[T]) []T {
+	result := []T{}
+	for item, ok := iter.Next(); ok; item, ok = iter.Next() {
+		result = append(result, item)
+	}
+	return result
+}
+
+type sliceIterator[T any] struct {
+	slice []T
+	index int
+}
+
+func (iter *sliceIterator[T]) HasNext() bool {
+	return iter.index < len(iter.slice)-1
+}
+
+func (iter *sliceIterator[T]) Next() (T, bool) {
+	iter.index++
+	ok := iter.index >= 0 && iter.index < len(iter.slice)
+	var item T
+	if ok {
+		item = iter.slice[iter.index]
+	}
+	return item, ok
+
+	// if len(iter.slice) == 0 {
+	// 	var zero T
+	// 	return zero, false
+	// }
+	// iter.index++
+	// item := iter.slice[0]
+	// iter.slice = iter.slice[1:]
+	// return item, true
+}
+
+// Prev implements PrevIterator.
+func (iter *sliceIterator[T]) Prev() {
+	if iter.index == -1 {
+		panic("Next function should be called Prev")
+	}
+	if iter.HasNext() {
+		iter.index--
+	} else {
+		iter.index = len(iter.slice) - 1
+	}
+}
+
+// Set implements SetIterator.
+func (iter *sliceIterator[T]) Set(value T) {
+	if iter.index == -1 {
+		panic("Next function should be called Set")
+	}
+	if iter.index >= len(iter.slice) || len(iter.slice) == 0 {
+		panic("No element in current iterator")
+	}
+	iter.slice[iter.index] = value
+}
+
+// FromRange creates a iterator which returns the numeric range between start inclusive and end
+// exclusive by the step size. start should be less than end, step shoud be positive.
+func FromRange[T lancetconstraints.Number](start, end, step T) Iterator[T] {
+	if end < start {
+		panic("RangeIterator: start should be before end")
+	} else if step <= 0 {
+		panic("RangeIterator: step should be positive")
+	}
+
+	return &rangeIterator[T]{start: start, end: end, step: step}
+}
+
+type rangeIterator[T lancetconstraints.Number] struct {
+	start, end, step T
+}
+
+func (iter *rangeIterator[T]) HasNext() bool {
+	if iter.start >= iter.end {
+		return false
+	}
+	return true
+}
+
+func (iter *rangeIterator[T]) Next() (T, bool) {
+	if iter.start >= iter.end {
+		var zero T
+		return zero, false
+	}
+	num := iter.start
+	iter.start += iter.step
+	return num, true
+}

iterator/iterator_test.go

@@ -0,0 +1,50 @@
+// Copyright 2022 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+// Package iterator implements some feature of C++ STL iterators
+package iterator
+
+import (
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestSliceIterator(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSliceIterator")
+
+	// HashNext
+	t.Run("slice iterator HasNext: ", func(t *testing.T) {
+		iter1 := FromSlice([]int{1, 2, 3, 4})
+		for {
+			item, _ := iter1.Next()
+
+			if item == 4 {
+				assert.Equal(false, iter1.HasNext())
+				break
+			} else {
+				assert.Equal(true, iter1.HasNext())
+			}
+		}
+
+		iter2 := FromSlice([]int{})
+		assert.Equal(false, iter2.HasNext())
+	})
+
+	//Next
+	t.Run("slice iterator Next: ", func(t *testing.T) {
+		iter1 := FromSlice([]int{1, 2, 3, 4})
+		for i := 0; i < 4; i++ {
+			item, ok := iter1.Next()
+			if !ok {
+				break
+			}
+			assert.Equal(i+1, item)
+		}
+
+		iter2 := FromSlice([]int{})
+		_, ok := iter2.Next()
+		assert.Equal(false, ok)
+	})
+
+}

iterator/operation.go

@@ -0,0 +1,61 @@
+// Copyright 2022 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+// Package iterator provides a way to iterate over values stored in containers.
+// note:
+// 1. Full feature iterator is complicated, this pacakge is just a experiment to explore how iterators could work in Go.
+// 2. The functionality of this package is very simple and limited, may not meet the actual dev needs.
+// 3. It is currently under development, unstable, and will not be completed for some time in the future.
+// So, based on above factors, you may not use it in production. but, anyone is welcome to improve it.
+// Hope that Go can support iterator in future. see https://github.com/golang/go/discussions/54245 and https://github.com/golang/go/discussions/56413
+package iterator
+
+// Map creates a new iterator which applies a function to all items of input iterator.
+func Map[T any, U any](iter Iterator[T], iteratee func(item T) U) Iterator[U] {
+	return &mapIterator[T, U]{
+		iter:     iter,
+		iteratee: iteratee,
+	}
+}
+
+type mapIterator[T any, U any] struct {
+	iter     Iterator[T]
+	iteratee func(T) U
+}
+
+func (mr *mapIterator[T, U]) HasNext() bool {
+	return mr.iter.HasNext()
+}
+
+func (mr *mapIterator[T, U]) Next() (U, bool) {
+	var zero U
+	item, ok := mr.iter.Next()
+	if !ok {
+		return zero, false
+	}
+	return mr.iteratee(item), true
+}
+
+// Filter creates a new iterator that returns only the items that pass specified predicate function.
+func Filter[T any](iter Iterator[T], predicateFunc func(item T) bool) Iterator[T] {
+	return &filterIterator[T]{iter: iter, predicateFunc: predicateFunc}
+}
+
+type filterIterator[T any] struct {
+	iter          Iterator[T]
+	predicateFunc func(T) bool
+}
+
+func (fr *filterIterator[T]) Next() (T, bool) {
+	for item, ok := fr.iter.Next(); ok; item, ok = fr.iter.Next() {
+		if fr.predicateFunc(item) {
+			return item, true
+		}
+	}
+	var zero T
+	return zero, false
+}
+
+func (fr *filterIterator[T]) HasNext() bool {
+	return fr.iter.HasNext()
+}

slice/slice.go

@@ -42,29 +42,18 @@ func Chunk[T any](slice []T, size int) [][]T {
 		return result
 	}
 
-	length := len(slice)
+	for _, item := range slice {
-	if size == 1 || size >= length {
+		l := len(result)
-		for _, v := range slice {
+		if l == 0 || len(result[l-1]) == size {
-			var tmp []T
+			result = append(result, []T{})
-			tmp = append(tmp, v)
+			l++
-			result = append(result, tmp)
 		}
-		return result
-	}
 
-	// divide slice equally
+		result[l-1] = append(result[l-1], item)
-	divideNum := length/size + 1
-	for i := 0; i < divideNum; i++ {
-		if i == divideNum-1 {
-			if len(slice[i*size:]) > 0 {
-				result = append(result, slice[i*size:])
-			}
-		} else {
-			result = append(result, slice[i*size:(i+1)*size])
-		}
 	}
 
 	return result
+
 }
 
 // Compact creates an slice with all falsey values removed. The values false, nil, 0, and "" are falsey
@@ -181,33 +170,29 @@ func EqualWith[T, U any](slice1 []T, slice2 []U, comparator func(T, U) bool) boo
 
 // Every return true if all of the values in the slice pass the predicate function.
 func Every[T any](slice []T, predicate func(index int, item T) bool) bool {
-	var currentLength int
-
 	for i, v := range slice {
-		if predicate(i, v) {
+		if !predicate(i, v) {
-			currentLength++
+			return false
 		}
 	}
 
-	return currentLength == len(slice)
+	return true
 }
 
 // None return true if all the values in the slice mismatch the criteria
 func None[T any](slice []T, predicate func(index int, item T) bool) bool {
-
+	l := 0
-	var currentLength int
 	for i, v := range slice {
 		if !predicate(i, v) {
-			currentLength++
+			l++
 		}
 	}
 
-	return currentLength == len(slice)
+	return l == len(slice)
 }
 
 // Some return true if any of the values in the list pass the predicate function.
 func Some[T any](slice []T, predicate func(index int, item T) bool) bool {
-
 	for i, v := range slice {
 		if predicate(i, v) {
 			return true
@@ -432,6 +417,15 @@ func ReplaceAll[T comparable](slice []T, old T, new T) []T {
 	return Replace(slice, old, new, -1)
 }
 
+// Repeat creates a slice with length n whose elements are param `item`.
+func Repeat[T any](item T, n int) []T {
+	result := make([]T, n)
+	for i := range result {
+		result[i] = item
+	}
+	return result
+}
+
 // InterfaceSlice convert param to slice of interface.
 func InterfaceSlice(slice any) []any {
 	sv := sliceValue(slice)
@@ -629,6 +623,17 @@ func UnionBy[T any, V comparable](predicate func(item T) V, slices ...[]T) []T {
 	return result
 }
 
+// Merge all given slices into one slice
+func Merge[T any](slices ...[]T) []T {
+	result := make([]T, 0)
+
+	for _, item := range slices {
+		result = append(result, item...)
+	}
+
+	return result
+}
+
 // Intersection creates a slice of unique values that included by all slices.
 func Intersection[T comparable](slices ...[]T) []T {
 	if len(slices) == 0 {

slice/slice_test.go

@@ -31,6 +31,10 @@ func TestChunk(t *testing.T) {
 
 	arr := []string{"a", "b", "c", "d", "e"}
 
+	assert.Equal([][]string{}, Chunk(arr, -1))
+
+	assert.Equal([][]string{}, Chunk(arr, 0))
+
 	r1 := [][]string{{"a"}, {"b"}, {"c"}, {"d"}, {"e"}}
 	assert.Equal(r1, Chunk(arr, 1))
 
@@ -43,8 +47,11 @@ func TestChunk(t *testing.T) {
 	r4 := [][]string{{"a", "b", "c", "d"}, {"e"}}
 	assert.Equal(r4, Chunk(arr, 4))
 
-	r5 := [][]string{{"a"}, {"b"}, {"c"}, {"d"}, {"e"}}
+	r5 := [][]string{{"a", "b", "c", "d", "e"}}
 	assert.Equal(r5, Chunk(arr, 5))
+
+	r6 := [][]string{{"a", "b", "c", "d", "e"}}
+	assert.Equal(r6, Chunk(arr, 6))
 }
 
 func TestCompact(t *testing.T) {
@@ -439,6 +446,18 @@ func TestUnionBy(t *testing.T) {
 	assert.Equal(result, []int{0, 2, 4, 10})
 }
 
+func TestMerge(t *testing.T) {
+	assert := internal.NewAssert(t, "TestMerge")
+
+	s1 := []int{1, 2, 3, 4}
+	s2 := []int{2, 3, 4, 5}
+	s3 := []int{4, 5, 6}
+
+	assert.Equal([]int{1, 2, 3, 4, 2, 3, 4, 5, 4, 5, 6}, Merge(s1, s2, s3))
+	assert.Equal([]int{1, 2, 3, 4, 2, 3, 4, 5}, Merge(s1, s2))
+	assert.Equal([]int{2, 3, 4, 5, 4, 5, 6}, Merge(s2, s3))
+}
+
 func TestIntersection(t *testing.T) {
 	s1 := []int{1, 2, 2, 3}
 	s2 := []int{1, 2, 3, 4}
@@ -665,3 +684,11 @@ func TestKeyBy(t *testing.T) {
 
 	assert.Equal(result, map[int]string{1: "a", 2: "ab", 3: "abc"})
 }
+
+func TestRepeat(t *testing.T) {
+	assert := internal.NewAssert(t, "TestRepeat")
+
+	result := Repeat("a", 6)
+
+	assert.Equal(result, []string{"a", "a", "a", "a", "a", "a"})
+}