1、私有方法提取到独立文件private.go里

2、新增StartOf和EndOf类方法

README.md

@@ -22,7 +22,7 @@ c := carbon.New().Timezone(carbon.PRC)
 >更多时区常量请查看[timezone.go](https://gitee.com/go-package/carbon/blob/master/timezone.go "timezone.go")文件
 
 #### 通用用法
-###### 获取当前时间字符串
+###### 获取当前时间
 ```go
 c.Now().Format("Y-m-d H:i:s") // 2020-09-08 13:00:00
 c.Now().Format("y-m-d h:i:s") // 20-09-08 01:00:00
@@ -37,14 +37,21 @@ c.Now().ToTimeString() // 13:00:00
 c.Now().ToTimestamp() // 1599272433
 ```
 
-###### 获取昨天、今天、明天时间字符串
+###### 获取昨天、今天、明天
 ```go
-c.Yesterday() // 2020-09-07 00:00:00
-c.Today() // 2020-09-08 00:00:00
-c.Tomorrow() // 2020-09-09 00:00:00
+c.Yesterday() // 2020-09-07
+c.Today() // 2020-09-08
+c.Tomorrow() // 2020-09-09
+
+c.StartOfYesterday() // 2020-09-07 00:00:00
+c.EndOfYesterday() // 2020-09-07 23:59:59
+c.StartOfToday() // 2020-09-08 00:00:00
+c.EndOfToday() // 2020-09-08 23:59:59
+c.StartOfTomorrow() // 2020-09-09 00:00:00
+c.EndOfTomorrow() // 2020-09-09 23:59:59
 ```
 
-###### 获取第一天、最后一天时间字符串
+###### 获取第一天、最后一天
 
 ```go
 // 年初

carbon.go

@@ -277,13 +277,13 @@ func (c *Carbon) Today() string {
 // StartOfToday 今天开始时间
 func (c *Carbon) StartOfToday() string {
 	now := time.Now()
-	return c.getStartDay(now)
+	return c.getStartDay(now).ToDateTimeString()
 }
 
 // EndOfToday 今天结束时间
 func (c *Carbon) EndOfToday() string {
 	now := time.Now()
-	return c.getEndDay(now)
+	return c.getEndDay(now).ToDateTimeString()
 }
 
 // Tomorrow 明天
@@ -295,13 +295,13 @@ func (c *Carbon) Tomorrow() string {
 // StartOfTomorrow 明天开始时间
 func (c *Carbon) StartOfTomorrow() string {
 	tomorrow := time.Now().AddDate(0, 0, 1)
-	return c.getStartDay(tomorrow)
+	return c.getStartDay(tomorrow).ToDateTimeString()
 }
 
 // EndOfTomorrow 明天结束时间
 func (c *Carbon) EndOfTomorrow() string {
 	tomorrow := time.Now().AddDate(0, 0, 1)
-	return c.getEndDay(tomorrow)
+	return c.getEndDay(tomorrow).ToDateTimeString()
 }
 
 // Yesterday 昨天
@@ -312,13 +312,13 @@ func (c *Carbon) Yesterday() string {
 // StartOfYesterday 昨天开始时间
 func (c *Carbon) StartOfYesterday() string {
 	yesterday := time.Now().AddDate(0, 0, -1)
-	return c.getStartDay(yesterday)
+	return c.getStartDay(yesterday).ToDateTimeString()
 }
 
 // EndOfYesterday 昨天结束时间
 func (c *Carbon) EndOfYesterday() string {
 	yesterday := time.Now().AddDate(0, 0, -1)
-	return c.getEndDay(yesterday)
+	return c.getEndDay(yesterday).ToDateTimeString()
 }
 
 // FirstDayInYear 年初第一天
@@ -333,12 +333,12 @@ func (c *Carbon) LastOfYear() string {
 
 // FirstDayInMonth 月初第一天
 func (c *Carbon) FirstOfMonth() string {
-	return c.CreateFromDate(c.Time.Year(), c.Time.Month(), 1).ToDateTimeString()
+	return c.getStartDay(c.Time).Format("2006-01-02 00:00:00")
 }
 
 // LastDayInMonth 月末最后一天
 func (c *Carbon) LastOfMonth() string {
-	return c.CreateFromDate(c.Time.Year(), c.Time.Month(), 1).Time.AddDate(0, 1, -1).Format("2006-01-02 00:00:00")
+	return c.getEndDay(c.Time).Format("2006-01-02 00:00:00")
 }
 
 // StartOfYear 当年开始时间
@@ -354,23 +354,23 @@ func (c *Carbon) EndOfYear() string {
 // StartOfMonth 当月开始时间
 func (c *Carbon) StartOfMonth() string {
 	t := c.CreateFromDate(c.Time.Year(), c.Time.Month(), c.Time.Day()).Time
-	return c.getStartDay(t)
+	return c.getStartDay(t).ToDateTimeString()
 }
 
 // EndOfMonth 当月结束时间
 func (c *Carbon) EndOfMonth() string {
 	t := c.CreateFromDate(c.Time.Year(), c.Time.Month(), c.Time.Day()).Time
-	return c.getEndDay(t)
+	return c.getEndDay(t).ToDateTimeString()
 }
 
 // FirstDayInMonth 当天开始时间
 func (c *Carbon) StartOfDay() string {
-	return c.getStartDay(c.Time)
+	return c.getStartDay(c.Time).ToDateTimeString()
 }
 
 // LastDayInMonth 当天结束时间
 func (c *Carbon) EndOfDay() string {
-	return c.getEndDay(c.Time)
+	return c.getEndDay(c.Time).ToDateTimeString()
 }
 
 // ToDateTimeString 转日期时间字符串

carbon_test.go

@@ -261,6 +261,6 @@ func TestCarbon_IsSunday(t *testing.T) {
 }
 
 func TestCarbon_StartOfDay(t *testing.T) {
-	a := New().Now().EndOfDay()
+	a := New().Now().FirstOfMonth()
 	fmt.Println(a)
 }

private.go

@@ -23,12 +23,12 @@ func format2layout(format string) string {
 }
 
 // getStartDay 获取开始日期
-func (c *Carbon) getStartDay(t time.Time) string {
-	return c.CreateFromDate(t.Year(), t.Month(), 01).Format("2006-01-02 15:04:05")
+func (c *Carbon) getStartDay(t time.Time) *Carbon {
+	return c.CreateFromDate(t.Year(), t.Month(), 01)
 }
 
 // getEndDay 获取结束日期
-func (c *Carbon) getEndDay(t time.Time) string {
+func (c *Carbon) getEndDay(t time.Time) *Carbon {
 	days := 30
 	if c.Time.Month() == time.February {
 		days = 28
@@ -36,5 +36,5 @@ func (c *Carbon) getEndDay(t time.Time) string {
 	if c.IsLeapYear() {
 		days = days + 1
 	}
-	return c.CreateFromDateTime(t.Year(), t.Month(), days-1, HoursPerDay-1, MinutesPerHour-1, SecondsPerMinute-1).Format("2006-01-02 15:04:05")
+	return c.CreateFromDateTime(t.Year(), t.Month(), days-1, HoursPerDay-1, MinutesPerHour-1, SecondsPerMinute-1)
 }