test&doc: add example and update doc for function package

README.md

@@ -414,14 +414,32 @@ import "github.com/duke-git/lancet/v2/function"
 
 #### Function list:
 
--   [After](https://github.com/duke-git/lancet/blob/main/docs/function.md#After)
--   [Before](https://github.com/duke-git/lancet/blob/main/docs/function.md#Before)
--   [Curry](https://github.com/duke-git/lancet/blob/main/docs/function.md#Curry)
--   [Compose](https://github.com/duke-git/lancet/blob/main/docs/function.md#Compose)
--   [Debounced](https://github.com/duke-git/lancet/blob/main/docs/function.md#Debounced)
--   [Delay](https://github.com/duke-git/lancet/blob/main/docs/function.md#Delay)
--   [Pipeline](https://github.com/duke-git/lancet/blob/main/docs/function.md#Pipeline)
--   [Watcher](https://github.com/duke-git/lancet/blob/main/docs/function.md#Watcher)
+-   **<big>After</big>** : return a function that invokes passed funcation once the returned function is called more than n times.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#After)]
+    [[play](https://go.dev/play/p/eRD5k2vzUVX)]
+-   **<big>Before</big>** : return a function that invokes passed funcation once the returned function is called less than n times
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Before)]
+    [[play](https://go.dev/play/p/0HqUDIFZ3IL)]
+-   **<big>CurryFn</big>** : make a curry function.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#CurryFn)]
+-   **<big>Compose</big>** : compose the functions from right to left.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Compose)]
+-   **<big>Delay</big>** : call the function after delayed time.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Delay)]
+    [[play](https://go.dev/play/p/Ivtc2ZE-Tye)]
+-   **<big>Debounced</big>** : creates a debounced function that delays invoking fn until after wait duration have elapsed since the last time the debounced function was invoked.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Debounced)]
+    [[play](https://go.dev/play/p/absuEGB_GN7)]
+-   **<big>Schedule</big>** : invoke function every duration time, util close the returned bool channel.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Schedule)]
+    [[play](https://go.dev/play/p/hbON-Xeyn5N)]
+-   **<big>Pipeline</big>** : takes a list of functions and returns a function whose param will be passed into the functions one by one.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Pipeline)]
+    [[play](https://go.dev/play/p/mPdUVvj6HD6)]
+-   **<big>Watcher</big>** : Watcher is used for record code excution time. can start/stop/reset the watch timer. get the elapsed time of function execution.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function.md#Watcher)]
+
+
 
 ### 11. Maputil package includes some functions to manipulate map.
 

README_zh-CN.md

@@ -413,14 +413,31 @@ import "github.com/duke-git/lancet/v2/function"
 
 #### 函数列表:
 
--   [After](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#After)
--   [Before](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Before)
--   [Curry](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Curry)
--   [Compose](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Compose)
--   [Debounced](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Debounced)
--   [Delay](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Delay)
--   [Pipeline](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Pipeline)
--   [Watcher](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Watcher)
+-   **<big>After</big>** : 创建一个函数，当该函数被调用n或更多次之后将执行传入的函数。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#After)]
+    [[play](https://go.dev/play/p/eRD5k2vzUVX)]
+-   **<big>Before</big>** : 创建一个函数，当该函数被调用不超过n次时，将执行执行传入的函数。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Before)]
+    [[play](https://go.dev/play/p/0HqUDIFZ3IL)]
+-   **<big>CurryFn</big>** : 创建柯里化函数。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#CurryFn)]
+-   **<big>Compose</big>** : 从右至左组合函数列表fnList，返回组合后的函数。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Compose)]
+-   **<big>Delay</big>** : 延迟delay时间后调用函数。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Delay)]
+    [[play](https://go.dev/play/p/Ivtc2ZE-Tye)]
+-   **<big>Debounced</big>** : 创建一个debounced函数，该函数延迟调用fn直到自上次调用debounced函数后等待持续时间过去。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Debounced)]
+    [[play](https://go.dev/play/p/absuEGB_GN7)]
+-   **<big>Schedule</big>** : 每次持续时间调用函数，直到关闭返回的channel。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Schedule)]
+    [[play](https://go.dev/play/p/hbON-Xeyn5N)]
+-   **<big>Pipeline</big>** : 从右至左执行函数列表。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Pipeline)]
+    [[play](https://go.dev/play/p/mPdUVvj6HD6)]
+-   **<big>Watcher</big>** : Watcher用于记录代码执行时间。可以启动/停止/重置手表定时器。获取函数执行的时间。
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/function_zh-CN.md#Watcher)]
+
 
 ### 11. maputil 包括一些操作 map 的函数.
 

docs/function.md

@@ -22,7 +22,7 @@ import (
 ## Index
 - [After](#After)
 - [Before](#Before)
-- [Curry](#Curry)
+- [CurryFn](#CurryFn)
 - [Compose](#Compose)
 - [Debounced](#Debounced)
 - [Delay](#Delay)
@@ -125,15 +125,15 @@ func main() {
 
 
 
-### <span id="Curry">Curry</span>
+### <span id="CurryFn">CurryFn</span>
 
-<p>Make a curry function.</p>
+<p>Make curry function.</p>
 
 <b>Signature:</b>
 
 ```go
-type Fn func(...any) any
-func (f Fn) Curry(i any) func(...any) any
+type CurryFn[T any] func(...T) T
+func (cf CurryFn[T]) New(val T) func(...T) T
 ```
 <b>Example:</b>
 
@@ -149,12 +149,15 @@ func main() {
     add := func(a, b int) int {
 		return a + b
 	}
-	var addCurry function.Fn = func(values ...any) any {
-		return add(values[0].(int), values[1].(int))
+
+	var addCurry CurryFn[int] = func(values ...int) int {
+		return add(values[0], values[1])
 	}
-	add1 := addCurry.Curry(1)
+	add1 := addCurry.New(1)
+
 	result := add1(2)
-    fmt.Println(result) //3
+
+	fmt.Println(result) //3
 }
 ```
 
@@ -167,7 +170,7 @@ func main() {
 <b>Signature:</b>
 
 ```go
-func Compose(fnList ...func(...any) any) func(...any) any
+func Compose[T any](fnList ...func(...T) T) func(...T) T
 ```
 <b>Example:</b>
 
@@ -180,17 +183,17 @@ import (
 )
 
 func main() {
-    add1 := func(v ...any) any {
-		return v[0].(int) + 1
+   	toUpper := func(strs ...string) string {
+		return strings.ToUpper(strs[0])
 	}
-    add2 := func(v ...any) any {
-		return v[0].(int) + 2
+	toLower := func(strs ...string) string {
+		return strings.ToLower(strs[0])
 	}
+	transform := Compose(toUpper, toLower)
 
-    add3 := function.Compose(add1, add2)
-	result := add3(1)
+	result := transform("aBCde")
 
-    fmt.Println(result) //4
+	fmt.Println(result) //ABCDE
 }
 ```
 
@@ -259,9 +262,9 @@ import (
 
 func main() {
 	var print = func(s string) {
-		fmt.Println(count) //test delay
+		fmt.Println(count) //delay 2 seconds
 	}
-	function.Delay(2*time.Second, print, "test delay")
+	function.Delay(2*time.Second, print, "delay 2 seconds")
 }
 ```
 
@@ -332,9 +335,9 @@ func main() {
 		return x * x
 	}
 
-	f := Pipeline(addOne, double, square)
+	fn := Pipeline(addOne, double, square)
 
-	fmt.Println(f(2)) //36
+	fmt.Println(fn(2)) //36
 }
 ```
 
@@ -351,6 +354,7 @@ type Watcher struct {
 	stopTime  int64
 	excuting  bool
 }
+func NewWatcher() *Watcher
 func (w *Watcher) Start() //start the watcher
 func (w *Watcher) Stop() //stop the watcher
 func (w *Watcher) Reset() //reset the watcher
@@ -367,7 +371,8 @@ import (
 )
 
 func main() {
-    w := &function.Watcher{}
+   	w := function.NewWatcher()
+
 	w.Start()
 
 	longRunningTask()
@@ -377,14 +382,10 @@ func main() {
 	w.Stop()
 
 	eapsedTime := w.GetElapsedTime().Milliseconds()
+	
 	fmt.Println(eapsedTime)
 
 	w.Reset()
-
-	fmt.Println(w.excuting) //false
-
-	fmt.Println(w.startTime) //0
-	fmt.Println(w.stopTime) //0
 }
 
 func longRunningTask() {

docs/function_zh-CN.md

@@ -22,7 +22,7 @@ import (
 ## 目录
 - [After](#After)
 - [Before](#Before)
-- [Curry](#Curry)
+- [CurryFn](#CurryFn)
 - [Compose](#Compose)
 - [Debounced](#Debounced)
 - [Delay](#Delay)
@@ -124,15 +124,15 @@ func main() {
 
 
 
-### <span id="Curry">Curry</span>
+### <span id="CurryFn">CurryFn</span>
 
-<p>创建一个柯里化的函数</p>
+<p>创建柯里化函数</p>
 
 <b>函数签名:</b>
 
 ```go
-type Fn func(...any) any
-func (f Fn) Curry(i any) func(...any) any
+type CurryFn[T any] func(...T) T
+func (cf CurryFn[T]) New(val T) func(...T) T
 ```
 <b>例子:</b>
 
@@ -148,11 +148,14 @@ func main() {
 	add := func(a, b int) int {
 		return a + b
 	}
-	var addCurry function.Fn = func(values ...any) any {
-		return add(values[0].(int), values[1].(int))
+
+	var addCurry CurryFn[int] = func(values ...int) int {
+		return add(values[0], values[1])
 	}
-	add1 := addCurry.Curry(1)
+	add1 := addCurry.New(1)
+
 	result := add1(2)
+
 	fmt.Println(result) //3
 }
 ```
@@ -161,12 +164,12 @@ func main() {
 
 ### <span id="Compose">Compose</span>
 
-<p>从右至左组合函数列表fnList， 返回组合后的函数</p>
+<p>从右至左组合函数列表fnList，返回组合后的函数</p>
 
 <b>函数签名:</b>
 
 ```go
-func Compose(fnList ...func(...any) any) func(...any) any
+func Compose[T any](fnList ...func(...T) T) func(...T) T
 ```
 <b>例子:</b>
 
@@ -179,17 +182,17 @@ import (
 )
 
 func main() {
-	add1 := func(v ...any) any {
-		return v[0].(int) + 1
+	toUpper := func(strs ...string) string {
+		return strings.ToUpper(strs[0])
 	}
-	add2 := func(v ...any) any {
-		return v[0].(int) + 2
+	toLower := func(strs ...string) string {
+		return strings.ToLower(strs[0])
 	}
+	transform := Compose(toUpper, toLower)
 
-	add3 := function.Compose(add1, add2)
-	result := add3(1)
+	result := transform("aBCde")
 
-	fmt.Println(result) //4
+	fmt.Println(result) //ABCDE
 }
 ```
 
@@ -197,7 +200,7 @@ func main() {
 
 ### <span id="Debounced">Debounced</span>
 
-<p>创建一个 debounced 函数，该函数延迟调用 fn 直到自上次调用 debounced 函数后等待持续时间过去。</p>
+<p>创建一个debounced函数，该函数延迟调用fn直到自上次调用debounced函数后等待持续时间过去。</p>
 
 <b>函数签名:</b>
 
@@ -333,7 +336,7 @@ func main() {
 
 	f := Pipeline(addOne, double, square)
 
-	fmt.Println(f(2)) //36
+	fmt.Println(fn(2)) //36
 }
 ```
 
@@ -341,7 +344,7 @@ func main() {
 
 ### <span id="Watcher">Watcher</span>
 
-<p>Watcher 用于记录代码执行时间。可以启动/停止/重置手表定时器。获取函数执行的时间。 </p>
+<p>Watcher用于记录代码执行时间。可以启动/停止/重置手表定时器。获取函数执行的时间。</p>
 
 <b>函数签名:</b>
 
@@ -351,6 +354,7 @@ type Watcher struct {
 	stopTime  int64
 	excuting  bool
 }
+func NewWatcher() *Watcher
 func (w *Watcher) Start() //start the watcher
 func (w *Watcher) Stop() //stop the watcher
 func (w *Watcher) Reset() //reset the watcher
@@ -367,7 +371,8 @@ import (
 )
 
 func main() {
-    w := &function.Watcher{}
+    w := function.NewWatcher()
+
 	w.Start()
 
 	longRunningTask()
@@ -377,14 +382,11 @@ func main() {
 	w.Stop()
 
 	eapsedTime := w.GetElapsedTime().Milliseconds()
+	
 	fmt.Println(eapsedTime)
 
 	w.Reset()
 
-	fmt.Println(w.excuting) //false
-
-	fmt.Println(w.startTime) //0
-	fmt.Println(w.stopTime) //0
 }
 
 func longRunningTask() {

function/function.go

@@ -5,11 +5,13 @@
 package function
 
 import (
+	"fmt"
 	"reflect"
 	"time"
 )
 
-// After creates a function that invokes func once it's called n or more times
+// After creates a function that invokes func once it's called n or more times.
+// Play: https://go.dev/play/p/8mQhkFmsgqs
 func After(n int, fn any) func(args ...any) []reflect.Value {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
@@ -23,7 +25,8 @@ func After(n int, fn any) func(args ...any) []reflect.Value {
 	}
 }
 
-// Before creates a function that invokes func once it's called less than n times
+// Before creates a function that invokes func once it's called less than n times.
+// Play: https://go.dev/play/p/0HqUDIFZ3IL
 func Before(n int, fn any) func(args ...any) []reflect.Value {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
@@ -40,41 +43,48 @@ func Before(n int, fn any) func(args ...any) []reflect.Value {
 	}
 }
 
-// Fn is for curry function which is func(...any) any
-type Fn func(...any) any
+// CurryFn is for make curry function
+type CurryFn[T any] func(...T) T
 
-// Curry make a curry function
-func (f Fn) Curry(i any) func(...any) any {
-	return func(values ...any) any {
-		v := append([]any{i}, values...)
-		return f(v...)
+// New make a curry function for specific value.
+// Play: Todo
+func (cf CurryFn[T]) New(val T) func(...T) T {
+	return func(vals ...T) T {
+		args := append([]T{val}, vals...)
+		return cf(args...)
 	}
 }
 
-// Compose compose the functions from right to left
-func Compose(fnList ...func(...any) any) func(...any) any {
-	return func(s ...any) any {
-		f := fnList[0]
-		restFn := fnList[1:]
+// Compose compose the functions from right to left.
+// Play: Todo
+func Compose[T any](fnList ...func(...T) T) func(...T) T {
+	return func(args ...T) T {
+		firstFn := fnList[0]
+		restFns := fnList[1:]
 
 		if len(fnList) == 1 {
-			return f(s...)
+			return firstFn(args...)
 		}
 
-		return f(Compose(restFn...)(s...))
+		fn := Compose(restFns...)
+		arg := fn(args...)
+
+		return firstFn(arg)
 	}
 }
 
-// Delay make the function execution after delayed time
+// Delay make the function execution after delayed time.
+// Play: https://go.dev/play/p/Ivtc2ZE-Tye
 func Delay(delay time.Duration, fn any, args ...any) {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
 
 	time.Sleep(delay)
-	invokeFunc(fn, args...)
+	unsafeInvokeFunc(fn, args...)
 }
 
 // Debounced creates a debounced function that delays invoking fn until after wait duration have elapsed since the last time the debounced function was invoked.
+// Play: https://go.dev/play/p/absuEGB_GN7
 func Debounced(fn func(), duration time.Duration) func() {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
@@ -92,7 +102,8 @@ func Debounced(fn func(), duration time.Duration) func() {
 	return func() { timer.Reset(duration) }
 }
 
-// Schedule invoke function every duration time, util close the returned bool chan
+// Schedule invoke function every duration time, util close the returned bool channel.
+// Play: https://go.dev/play/p/hbON-Xeyn5N
 func Schedule(d time.Duration, fn any, args ...any) chan bool {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
@@ -114,6 +125,7 @@ func Schedule(d time.Duration, fn any, args ...any) chan bool {
 
 // Pipeline takes a list of functions and returns a function whose param will be passed into
 // the functions one by one.
+// Play: https://go.dev/play/p/mPdUVvj6HD6
 func Pipeline[T any](funcs ...func(T) T) func(T) T {
 	return func(arg T) (result T) {
 		result = arg
@@ -123,3 +135,27 @@ func Pipeline[T any](funcs ...func(T) T) func(T) T {
 		return
 	}
 }
+
+func unsafeInvokeFunc(fn any, args ...any) []reflect.Value {
+	fv := reflect.ValueOf(fn)
+	params := make([]reflect.Value, len(args))
+	for i, item := range args {
+		params[i] = reflect.ValueOf(item)
+	}
+	return fv.Call(params)
+}
+
+func functionValue(function any) reflect.Value {
+	v := reflect.ValueOf(function)
+	if v.Kind() != reflect.Func {
+		panic(fmt.Sprintf("Invalid function type, value of type %T", function))
+	}
+	return v
+}
+
+func mustBeFunction(function any) {
+	v := reflect.ValueOf(function)
+	if v.Kind() != reflect.Func {
+		panic(fmt.Sprintf("Invalid function type, value of type %T", function))
+	}
+}

function/function_example_test.go

@@ -0,0 +1,147 @@
+package function
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+func ExampleAfter() {
+	fn := After(2, func() {
+		fmt.Println("test")
+	})
+
+	fn()
+	fn()
+
+	// Output:
+	// test
+}
+
+func ExampleBefore() {
+	fn := Before(2, func() {
+		fmt.Println("test")
+	})
+
+	fn()
+	fn()
+	fn()
+	fn()
+
+	// Output:
+	// test
+	// test
+}
+
+func ExampleCurryFn_New() {
+	add := func(a, b int) int {
+		return a + b
+	}
+
+	var addCurry CurryFn[int] = func(values ...int) int {
+		return add(values[0], values[1])
+	}
+	add1 := addCurry.New(1)
+
+	result := add1(2)
+
+	fmt.Println(result)
+
+	// Output:
+	// 3
+}
+
+func ExampleCompose() {
+	toUpper := func(strs ...string) string {
+		return strings.ToUpper(strs[0])
+	}
+	toLower := func(strs ...string) string {
+		return strings.ToLower(strs[0])
+	}
+	transform := Compose(toUpper, toLower)
+
+	result := transform("aBCde")
+
+	fmt.Println(result)
+
+	// Output:
+	// ABCDE
+}
+
+func ExampleDelay() {
+	var print = func(s string) {
+		fmt.Println(s)
+	}
+
+	Delay(2*time.Second, print, "hello")
+
+	// Output:
+	// hello
+}
+
+func ExampleDebounced() {
+	count := 0
+	add := func() {
+		count++
+	}
+
+	debouncedAdd := Debounced(add, 50*time.Microsecond)
+
+	debouncedAdd()
+	debouncedAdd()
+	debouncedAdd()
+	debouncedAdd()
+
+	time.Sleep(100 * time.Millisecond)
+
+	fmt.Println(count)
+
+	debouncedAdd()
+
+	time.Sleep(100 * time.Millisecond)
+
+	fmt.Println(count)
+
+	// Output:
+	// 1
+	// 2
+}
+
+func ExampleSchedule() {
+	var result []string
+
+	appendFn := func(s string) {
+		result = append(result, s)
+	}
+
+	stop := Schedule(1*time.Second, appendFn, "*")
+
+	time.Sleep(3 * time.Second)
+	close(stop)
+
+	fmt.Println(result)
+
+	// Output:
+	// [* * *]
+}
+
+func ExamplePipeline() {
+	addOne := func(x int) int {
+		return x + 1
+	}
+	double := func(x int) int {
+		return 2 * x
+	}
+	square := func(x int) int {
+		return x * x
+	}
+
+	fn := Pipeline(addOne, double, square)
+
+	result := fn(2)
+
+	fmt.Println(result)
+
+	// Output:
+	// 36
+}

function/function_internal.go

@@ -1,39 +0,0 @@
-package function
-
-import (
-	"fmt"
-	"reflect"
-)
-
-func invokeFunc(fn any, args ...any) []reflect.Value {
-	fv := functionValue(fn)
-	params := make([]reflect.Value, len(args))
-	for i, item := range args {
-		params[i] = reflect.ValueOf(item)
-	}
-	return fv.Call(params)
-}
-
-func unsafeInvokeFunc(fn any, args ...any) []reflect.Value {
-	fv := reflect.ValueOf(fn)
-	params := make([]reflect.Value, len(args))
-	for i, item := range args {
-		params[i] = reflect.ValueOf(item)
-	}
-	return fv.Call(params)
-}
-
-func functionValue(function any) reflect.Value {
-	v := reflect.ValueOf(function)
-	if v.Kind() != reflect.Func {
-		panic(fmt.Sprintf("Invalid function type, value of type %T", function))
-	}
-	return v
-}
-
-func mustBeFunction(function any) {
-	v := reflect.ValueOf(function)
-	if v.Kind() != reflect.Func {
-		panic(fmt.Sprintf("Invalid function type, value of type %T", function))
-	}
-}

function/function_test.go

@@ -62,24 +62,26 @@ func TestCurry(t *testing.T) {
 	add := func(a, b int) int {
 		return a + b
 	}
-	var addCurry Fn = func(values ...any) any {
-		return add(values[0].(int), values[1].(int))
+	var addCurry CurryFn[int] = func(values ...int) int {
+		return add(values[0], values[1])
 	}
-	add1 := addCurry.Curry(1)
+	add1 := addCurry.New(1)
+
 	assert.Equal(3, add1(2))
 }
 
 func TestCompose(t *testing.T) {
 	assert := internal.NewAssert(t, "TestCompose")
 
-	toUpper := func(a ...any) any {
-		return strings.ToUpper(a[0].(string))
+	toUpper := func(strs ...string) string {
+		return strings.ToUpper(strs[0])
 	}
-	toLower := func(a ...any) any {
-		return strings.ToLower(a[0].(string))
+	toLower := func(strs ...string) string {
+		return strings.ToLower(strs[0])
 	}
 
 	expected := toUpper(toLower("aBCde"))
+
 	cf := Compose(toUpper, toLower)
 	res := cf("aBCde")
 

function/watcher.go

@@ -3,12 +3,18 @@ package function
 import "time"
 
 // Watcher is used for record code excution time
+// Play: Todo
 type Watcher struct {
 	startTime int64
 	stopTime  int64
 	excuting  bool
 }
 
+// Start the watch timer.
+func NewWatcher() *Watcher {
+	return &Watcher{}
+}
+
 // Start the watch timer.
 func (w *Watcher) Start() {
 	w.startTime = time.Now().UnixNano()

function/watcher_example_test.go

@@ -0,0 +1,22 @@
+package function
+
+import "fmt"
+
+func ExampleWatcher() {
+	w := NewWatcher()
+
+	w.Start()
+
+	longRunningTask()
+
+	w.Stop()
+
+	// eapsedTime := w.GetElapsedTime().Milliseconds()
+
+	fmt.Println("foo")
+
+	w.Reset()
+
+	// Output:
+	// foo
+}

function/watcher_test.go

@@ -9,7 +9,7 @@ import (
 func TestWatcher(t *testing.T) {
 	assert := internal.NewAssert(t, "TestWatcher")
 
-	w := &Watcher{}
+	w := NewWatcher()
 	w.Start()
 
 	longRunningTask()