diff --git a/concurrency/channel.go b/concurrency/channel.go
index fad8333..9f40dd3 100644
--- a/concurrency/channel.go
+++ b/concurrency/channel.go
@@ -158,7 +158,7 @@ func (c *Channel) Bridge(ctx context.Context, chanStream <-chan <-chan any) <-ch
 			var stream <-chan any
 			select {
 			case maybeStream, ok := <-chanStream:
-				if ok == false {
+				if !ok {
 					return
 				}
 				stream = maybeStream
diff --git a/convertor/convertor.go b/convertor/convertor.go
index 265246b..9d9996d 100644
--- a/convertor/convertor.go
+++ b/convertor/convertor.go
@@ -97,38 +97,41 @@ func ToString(value any) string {
 		return ""
 	}
 
-	switch value.(type) {
+	switch val := value.(type) {
 	case float32:
-		return strconv.FormatFloat(float64(value.(float32)), 'f', -1, 32)
+		return strconv.FormatFloat(float64(val), 'f', -1, 32)
 	case float64:
-		return strconv.FormatFloat(value.(float64), 'f', -1, 64)
+		return strconv.FormatFloat(val, 'f', -1, 64)
 	case int:
-		return strconv.FormatInt(int64(value.(int)), 10)
+		return strconv.FormatInt(int64(val), 10)
 	case int8:
-		return strconv.FormatInt(int64(value.(int8)), 10)
+		return strconv.FormatInt(int64(val), 10)
 	case int16:
-		return strconv.FormatInt(int64(value.(int16)), 10)
+		return strconv.FormatInt(int64(val), 10)
 	case int32:
-		return strconv.FormatInt(int64(value.(int32)), 10)
+		return strconv.FormatInt(int64(val), 10)
 	case int64:
-		return strconv.FormatInt(value.(int64), 10)
+		return strconv.FormatInt(val, 10)
 	case uint:
-		return strconv.FormatUint(uint64(value.(uint)), 10)
+		return strconv.FormatUint(uint64(val), 10)
 	case uint8:
-		return strconv.FormatUint(uint64(value.(uint8)), 10)
+		return strconv.FormatUint(uint64(val), 10)
 	case uint16:
-		return strconv.FormatUint(uint64(value.(uint16)), 10)
+		return strconv.FormatUint(uint64(val), 10)
 	case uint32:
-		return strconv.FormatUint(uint64(value.(uint32)), 10)
+		return strconv.FormatUint(uint64(val), 10)
 	case uint64:
-		return strconv.FormatUint(value.(uint64), 10)
+		return strconv.FormatUint(val, 10)
 	case string:
-		return value.(string)
+		return val
 	case []byte:
-		return string(value.([]byte))
+		return string(val)
 	default:
-		newValue, _ := json.Marshal(value)
-		return string(newValue)
+		b, err := json.Marshal(val)
+		if err != nil {
+			return ""
+		}
+		return string(b)
 
 		// todo: maybe we should't supprt other type conversion
 		// v := reflect.ValueOf(value)
diff --git a/convertor/convertor_test.go b/convertor/convertor_test.go
index 512cab7..fbfd81c 100644
--- a/convertor/convertor_test.go
+++ b/convertor/convertor_test.go
@@ -27,14 +27,9 @@ func TestToChannel(t *testing.T) {
 	assert := internal.NewAssert(t, "TestToChannel")
 
 	ch := ToChannel([]int{1, 2, 3})
-	val1, _ := <-ch
-	assert.Equal(1, val1)
-
-	val2, _ := <-ch
-	assert.Equal(2, val2)
-
-	val3, _ := <-ch
-	assert.Equal(3, val3)
+	assert.Equal(1, <-ch)
+	assert.Equal(2, <-ch)
+	assert.Equal(3, <-ch)
 
 	_, ok := <-ch
 	assert.Equal(false, ok)
@@ -254,6 +249,7 @@ func TestDecodeByte(t *testing.T) {
 
 	var obj string
 	byteData := []byte{6, 12, 0, 3, 97, 98, 99}
-	DecodeByte(byteData, &obj)
+	err := DecodeByte(byteData, &obj)
+	assert.IsNil(err)
 	assert.Equal("abc", obj)
 }
diff --git a/cryptor/rsa.go b/cryptor/rsa.go
index 4b8440a..27a43e4 100644
--- a/cryptor/rsa.go
+++ b/cryptor/rsa.go
@@ -33,7 +33,11 @@ func GenerateRsaKey(keySize int, priKeyFile, pubKeyFile string) error {
 	if err != nil {
 		panic(err)
 	}
-	pem.Encode(file, &block)
+	err = pem.Encode(file, &block)
+	if err != nil {
+		return err
+	}
+
 	file.Close()
 
 	// public key
@@ -49,12 +53,16 @@ func GenerateRsaKey(keySize int, priKeyFile, pubKeyFile string) error {
 		Bytes: derpText,
 	}
 
-	//file,err = os.Create("rsa_public.pem")
 	file, err = os.Create(pubKeyFile)
 	if err != nil {
 		return err
 	}
-	pem.Encode(file, &block)
+
+	err = pem.Encode(file, &block)
+	if err != nil {
+		return err
+	}
+
 	file.Close()
 
 	return nil
@@ -72,7 +80,11 @@ func RsaEncrypt(data []byte, pubKeyFileName string) []byte {
 	}
 	defer file.Close()
 	buf := make([]byte, fileInfo.Size())
-	file.Read(buf)
+
+	_, err = file.Read(buf)
+	if err != nil {
+		panic(err)
+	}
 
 	block, _ := pem.Decode(buf)
 
@@ -101,7 +113,12 @@ func RsaDecrypt(data []byte, privateKeyFileName string) []byte {
 	}
 	buf := make([]byte, fileInfo.Size())
 	defer file.Close()
+
 	file.Read(buf)
+	_, err = file.Read(buf)
+	if err != nil {
+		panic(err)
+	}
 
 	block, _ := pem.Decode(buf)
 
diff --git a/datastructure/heap/maxheap.go b/datastructure/heap/maxheap.go
index 595d044..1fa56cc 100644
--- a/datastructure/heap/maxheap.go
+++ b/datastructure/heap/maxheap.go
@@ -146,9 +146,9 @@ func (h *MaxHeap[T]) PrintStructure() {
 	lastNum := powerTwo(level - 1)
 	lastLen := lastNum + (lastNum - 1)
 
-	heapTree := make([][]string, level, level)
+	heapTree := make([][]string, level)
 	for i := 0; i < level; i++ {
-		heapTree[i] = make([]string, lastLen, lastLen)
+		heapTree[i] = make([]string, lastLen)
 		for j := 0; j < lastLen; j++ {
 			heapTree[i][j] = ""
 		}
@@ -169,9 +169,9 @@ func (h *MaxHeap[T]) PrintStructure() {
 		for n := 0; n < lastLen; n++ {
 			val := heapTree[m][n]
 			if val == "" {
-				fmt.Printf(" ")
+				fmt.Print(" ")
 			} else {
-				fmt.Printf(val)
+				fmt.Print(val)
 			}
 		}
 		fmt.Println()
diff --git a/datastructure/list/list.go b/datastructure/list/list.go
index 0f99123..199dd59 100644
--- a/datastructure/list/list.go
+++ b/datastructure/list/list.go
@@ -156,7 +156,7 @@ func (l *List[T]) DeleteAt(index int) {
 		return
 	}
 	if index == size-1 {
-		data = append(data[:index])
+		data = data[:index]
 	} else {
 		data = append(data[:index], data[index+1:]...)
 	}
@@ -174,7 +174,7 @@ func (l *List[T]) DeleteIf(f func(T) bool) int {
 			continue
 		}
 		if index == size-1 {
-			data = append(data[:index])
+			data = data[:index]
 		} else {
 			data = append(data[:index], data[index+1:]...)
 			index--
@@ -221,7 +221,7 @@ func (l *List[T]) IsEmpty() bool {
 
 // Clear the data of list
 func (l *List[T]) Clear() {
-	l.data = make([]T, 0, 0)
+	l.data = make([]T, 0)
 }
 
 // Clone return a copy of list
@@ -235,7 +235,7 @@ func (l *List[T]) Clone() *List[T] {
 // Merge two list, return new list, don't change original list
 func (l *List[T]) Merge(other *List[T]) *List[T] {
 	l1, l2 := len(l.data), len(other.data)
-	ml := NewList(make([]T, l1+l2, l1+l2))
+	ml := NewList(make([]T, l1+l2))
 
 	data := append([]T{}, append(l.data, other.data...)...)
 	ml.data = data
@@ -274,7 +274,7 @@ func (l *List[T]) Unique() {
 	data := l.data
 	size := len(data)
 
-	uniqueData := make([]T, 0, 0)
+	uniqueData := make([]T, 0)
 	for i := 0; i < size; i++ {
 		value := data[i]
 		skip := true
@@ -305,7 +305,7 @@ func (l *List[T]) Union(other *List[T]) *List[T] {
 
 // Intersection creates a new list whose element both be contained in list l and other
 func (l *List[T]) Intersection(other *List[T]) *List[T] {
-	result := NewList(make([]T, 0, 0))
+	result := NewList(make([]T, 0))
 
 	for _, v := range l.data {
 		if other.Contain(v) {
diff --git a/datastructure/tree/tree_internal.go b/datastructure/tree/tree_internal.go
index ccc28f3..940fe25 100644
--- a/datastructure/tree/tree_internal.go
+++ b/datastructure/tree/tree_internal.go
@@ -38,35 +38,35 @@ func inOrderTraverse[T any](node *datastructure.TreeNode[T]) []T {
 	return data
 }
 
-func preOrderPrint[T any](node *datastructure.TreeNode[T]) {
-	if node == nil {
-		return
-	}
+// func preOrderPrint[T any](node *datastructure.TreeNode[T]) {
+// 	if node == nil {
+// 		return
+// 	}
 
-	fmt.Printf("%v, ", node.Value)
-	preOrderPrint(node.Left)
-	preOrderPrint(node.Right)
-}
+// 	fmt.Printf("%v, ", node.Value)
+// 	preOrderPrint(node.Left)
+// 	preOrderPrint(node.Right)
+// }
 
-func postOrderPrint[T any](node *datastructure.TreeNode[T]) {
-	if node == nil {
-		return
-	}
+// func postOrderPrint[T any](node *datastructure.TreeNode[T]) {
+// 	if node == nil {
+// 		return
+// 	}
 
-	preOrderPrint(node.Left)
-	preOrderPrint(node.Right)
-	fmt.Printf("%v, ", node.Value)
-}
+// 	postOrderPrint(node.Left)
+// 	postOrderPrint(node.Right)
+// 	fmt.Printf("%v, ", node.Value)
+// }
 
-func inOrderPrint[T any](node *datastructure.TreeNode[T]) {
-	if node == nil {
-		return
-	}
+// func inOrderPrint[T any](node *datastructure.TreeNode[T]) {
+// 	if node == nil {
+// 		return
+// 	}
 
-	inOrderPrint(node.Left)
-	fmt.Printf("%v, ", node.Value)
-	inOrderPrint(node.Right)
-}
+// 	inOrderPrint(node.Left)
+// 	fmt.Printf("%v, ", node.Value)
+// 	inOrderPrint(node.Right)
+// }
 
 func levelOrderTraverse[T any](root *datastructure.TreeNode[T], traversal *[]T) {
 	var q []*datastructure.TreeNode[T] // queue
diff --git a/fileutil/file.go b/fileutil/file.go
index efa8c14..6423eef 100644
--- a/fileutil/file.go
+++ b/fileutil/file.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"path"
@@ -78,13 +77,16 @@ func CopyFile(srcFilePath string, dstFilePath string) error {
 	var tmp = make([]byte, 1024*4)
 	for {
 		n, err := srcFile.Read(tmp)
-		distFile.Write(tmp[:n])
 		if err != nil {
 			if err == io.EOF {
 				return nil
 			}
 			return err
 		}
+		_, err = distFile.Write(tmp[:n])
+		if err != nil {
+			return err
+		}
 	}
 }
 
@@ -102,7 +104,7 @@ func ClearFile(path string) error {
 
 //ReadFileToString return string of file content
 func ReadFileToString(path string) (string, error) {
-	bytes, err := ioutil.ReadFile(path)
+	bytes, err := os.ReadFile(path)
 	if err != nil {
 		return "", err
 	}
@@ -141,7 +143,7 @@ func ListFileNames(path string) ([]string, error) {
 		return []string{}, nil
 	}
 
-	fs, err := ioutil.ReadDir(path)
+	fs, err := os.ReadDir(path)
 	if err != nil {
 		return []string{}, err
 	}
@@ -172,7 +174,7 @@ func Zip(fpath string, destPath string) error {
 	archive := zip.NewWriter(zipFile)
 	defer archive.Close()
 
-	filepath.Walk(fpath, func(path string, info os.FileInfo, err error) error {
+	err = filepath.Walk(fpath, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
@@ -209,6 +211,10 @@ func Zip(fpath string, destPath string) error {
 		return nil
 	})
 
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -229,9 +235,13 @@ func UnZip(zipFile string, destPath string) error {
 		}
 
 		if f.FileInfo().IsDir() {
-			os.MkdirAll(path, os.ModePerm)
+			err = os.MkdirAll(path, os.ModePerm)
+			if err != nil {
+				return err
+			}
 		} else {
-			if err = os.MkdirAll(filepath.Dir(path), os.ModePerm); err != nil {
+			err = os.MkdirAll(filepath.Dir(path), os.ModePerm)
+			if err != nil {
 				return err
 			}
 
diff --git a/fileutil/file_test.go b/fileutil/file_test.go
index 607fce4..6530a5a 100644
--- a/fileutil/file_test.go
+++ b/fileutil/file_test.go
@@ -25,9 +25,10 @@ func TestCreateFile(t *testing.T) {
 	f := "./text.txt"
 	if CreateFile(f) {
 		file, err := os.Open(f)
-		defer file.Close()
 		assert.IsNil(err)
 		assert.Equal(f, file.Name())
+
+		defer file.Close()
 	} else {
 		t.FailNow()
 	}
@@ -113,7 +114,11 @@ func TestReadFileToString(t *testing.T) {
 
 	f, _ := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC, 0777)
 	defer f.Close()
-	f.WriteString("hello world")
+
+	_, err := f.WriteString("hello world")
+	if err != nil {
+		t.Log(err)
+	}
 
 	content, _ := ReadFileToString(path)
 	assert.Equal("hello world", content)
@@ -130,9 +135,12 @@ func TestClearFile(t *testing.T) {
 	f, _ := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC, 0777)
 	defer f.Close()
 
-	f.WriteString("hello world")
+	_, err := f.WriteString("hello world")
+	if err != nil {
+		t.Log(err)
+	}
 
-	err := ClearFile(path)
+	err = ClearFile(path)
 	assert.IsNil(err)
 
 	content, _ := ReadFileToString(path)
@@ -148,8 +156,13 @@ func TestReadFileByLine(t *testing.T) {
 	CreateFile(path)
 
 	f, _ := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC, 0777)
+
 	defer f.Close()
-	f.WriteString("hello\nworld")
+
+	_, err := f.WriteString("hello\nworld")
+	if err != nil {
+		t.Log(err)
+	}
 
 	expected := []string{"hello", "world"}
 	actual, _ := ReadFileByLine(path)
diff --git a/function/function.go b/function/function.go
index c6356c8..6846696 100644
--- a/function/function.go
+++ b/function/function.go
@@ -84,10 +84,8 @@ func Debounced(fn func(), duration time.Duration) func() {
 
 	go func() {
 		for {
-			select {
-			case <-timer.C:
-				go fn()
-			}
+			<-timer.C
+			go fn()
 		}
 	}()
 
diff --git a/iterator/iterator.go b/iterator/iterator.go
index 4b899de..f55ade4 100644
--- a/iterator/iterator.go
+++ b/iterator/iterator.go
@@ -157,10 +157,7 @@ type rangeIterator[T lancetconstraints.Number] struct {
 }
 
 func (iter *rangeIterator[T]) HasNext() bool {
-	if iter.start >= iter.end {
-		return false
-	}
-	return true
+	return iter.start < iter.end
 }
 
 func (iter *rangeIterator[T]) Next() (T, bool) {
diff --git a/maputil/map.go b/maputil/map.go
index 55d08e1..bf63196 100644
--- a/maputil/map.go
+++ b/maputil/map.go
@@ -85,7 +85,7 @@ func Intersect[K comparable, V any](maps ...map[K]V) map[K]V {
 		return m
 	}
 
-	reduceMaps := make([]map[K]V, 2, 2)
+	reduceMaps := make([]map[K]V, 2)
 	result = reducer(maps[0], maps[1])
 
 	for i := 2; i < len(maps); i++ {
diff --git a/netutil/http_client.go b/netutil/http_client.go
index 030d936..5bf71cf 100644
--- a/netutil/http_client.go
+++ b/netutil/http_client.go
@@ -108,7 +108,11 @@ func (client *HttpClient) SendRequest(request *HttpRequest) (*http.Response, err
 
 	client.setTLS(rawUrl)
 	client.setHeader(req, request.Headers)
-	client.setQueryParam(req, rawUrl, request.QueryParams)
+
+	err = client.setQueryParam(req, rawUrl, request.QueryParams)
+	if err != nil {
+		return nil, err
+	}
 
 	if request.FormData != nil {
 		client.setFormData(req, request.FormData)
diff --git a/netutil/http_client_test.go b/netutil/http_client_test.go
index ceb9ce1..97f436d 100644
--- a/netutil/http_client_test.go
+++ b/netutil/http_client_test.go
@@ -32,7 +32,10 @@ func TestHttpClient_Get(t *testing.T) {
 	}
 
 	var todo Todo
-	httpClient.DecodeResponse(resp, &todo)
+	err = httpClient.DecodeResponse(resp, &todo)
+	if err != nil {
+		t.Log(err)
+	}
 
 	assert.Equal(1, todo.Id)
 }
diff --git a/netutil/http_test.go b/netutil/http_test.go
index a9f0d3f..b530bea 100644
--- a/netutil/http_test.go
+++ b/netutil/http_test.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"log"
+	"net/url"
 	"testing"
 
 	"github.com/duke-git/lancet/v2/internal"
@@ -54,13 +55,13 @@ func TestHttpPostFormData(t *testing.T) {
 		UserId int    `json:"userId"`
 		Title  string `json:"title"`
 	}
-	// postData := url.Values{}
-	// postData.Add("userId", "1")
-	// postData.Add("title", "TestAddToDo")
+	postData := url.Values{}
+	postData.Add("userId", "1")
+	postData.Add("title", "TestToDo")
 
-	postData := make(map[string]string)
-	postData["userId"] = "1"
-	postData["title"] = "title"
+	// postData := make(map[string]string)
+	// postData["userId"] = "1"
+	// postData["title"] = "title"
 
 	resp, err := HttpPost(apiUrl, header, postData, nil)
 	if err != nil {
diff --git a/netutil/net.go b/netutil/net.go
index 6960de0..cb62aaf 100644
--- a/netutil/net.go
+++ b/netutil/net.go
@@ -2,7 +2,7 @@ package netutil
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -55,7 +55,7 @@ func GetPublicIpInfo() (*PublicIpInfo, error) {
 	}
 	defer resp.Body.Close()
 
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, err
 	}
diff --git a/system/os_test.go b/system/os_test.go
index a21cbd9..d084c15 100644
--- a/system/os_test.go
+++ b/system/os_test.go
@@ -25,7 +25,9 @@ func TestOsEnvOperation(t *testing.T) {
 	envNotExist := GetOsEnv("foo")
 	assert.Equal("", envNotExist)
 
-	SetOsEnv("foo", "foo_value")
+	err := SetOsEnv("foo", "foo_value")
+	assert.IsNil(err)
+
 	envExist := GetOsEnv("foo")
 	assert.Equal("foo_value", envExist)
 
@@ -34,7 +36,7 @@ func TestOsEnvOperation(t *testing.T) {
 	assert.Equal(false, CompareOsEnv("abc", "abc"))
 	assert.Equal(false, CompareOsEnv("abc", "abc"))
 
-	err := RemoveOsEnv("foo")
+	err = RemoveOsEnv("foo")
 	if err != nil {
 		t.Fail()
 	}