feat: add IsLeapYear

docs/datetime.md

@@ -53,6 +53,7 @@ import (
 -   [ToFormat](#ToFormat)
 -   [ToFormatForTpl](#ToFormatForTpl)
 -   [ToIso8601](#ToIso8601)
+-   [IsLeapYear](#IsLeapYear)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -607,8 +608,8 @@ func main() {
     now := time.Now()
     currentDate := datetime.GetNowDate()
 
-    fmt.Println(currentDate) 
-    
+    fmt.Println(currentDate)
+
     // Output:
     // 2022-01-28
 }
@@ -671,8 +672,8 @@ func main() {
     now := time.Now()
     current := datetime.GetNowDateTime()
 
-    fmt.Println(current) 
-    
+    fmt.Println(current)
+
     // Output:
     // 2022-01-28 15:59:33
 }
@@ -702,9 +703,9 @@ import (
 func main() {
     now := time.Now()
     zeroTime := datetime.GetZeroHourTimestamp()
-    
-    fmt.Println(zeroTime) 
-    
+
+    fmt.Println(zeroTime)
+
     // Output:
     // 1643299200
 }
@@ -735,8 +736,8 @@ func main() {
     now := time.Now()
     nightTime := datetime.GetNightTimestamp()
 
-    fmt.Println(nightTime) 
-    
+    fmt.Println(nightTime)
+
     // Output:
     // 1643385599
 }
@@ -842,8 +843,8 @@ import (
 
 func main() {
     tm := datetime.NewUnixNow()
-    fmt.Println(tm) 
-    
+    fmt.Println(tm)
+
     // Output:
     // &{1647597438}
 }
@@ -874,8 +875,8 @@ import (
 
 func main() {
     tm := datetime.NewUnix(1647597438)
-    fmt.Println(tm) 
-    
+    fmt.Println(tm)
+
     // Output:
     // &{1647597438}
 }
@@ -906,8 +907,8 @@ import (
 
 func main() {
     tm, err := datetime.NewFormat("2022-03-18 17:04:05")
-    fmt.Println(tm) 
-    
+    fmt.Println(tm)
+
     // Output:
     // &{1647594245}
 }
@@ -938,8 +939,8 @@ import (
 
 func main() {
     tm, err := datetime.NewISO8601("2006-01-02T15:04:05.999Z")
-    fmt.Println(tm) 
-    
+    fmt.Println(tm)
+
     // Output:
     // &{1136214245}
 }
@@ -967,8 +968,8 @@ import (
 
 func main() {
     tm := datetime.NewUnixNow()
-    fmt.Println(tm.ToUnix()) 
-    
+    fmt.Println(tm.ToUnix())
+
     // Output:
     // 1647597438
 }
@@ -996,8 +997,8 @@ import (
 
 func main() {
     tm, _ := datetime.NewFormat("2022-03-18 17:04:05")
-    fmt.Println(tm.ToFormat()) 
-    
+    fmt.Println(tm.ToFormat())
+
     // Output:
     // 2022-03-18 17:04:05
 }
@@ -1026,8 +1027,8 @@ import (
 func main() {
     tm, _ := datetime.NewFormat("2022-03-18 17:04:05")
     ts := tm.ToFormatForTpl("2006/01/02 15:04:05")
-    fmt.Println(ts) 
-    
+    fmt.Println(ts)
+
     // Output:
     // 2022/03/18 17:04:05
 }
@@ -1056,9 +1057,43 @@ import (
 func main() {
     tm, _ := datetime.NewISO8601("2006-01-02T15:04:05.999Z")
     ts := tm.ToIso8601()
-    fmt.Println(ts) 
-    
+    fmt.Println(ts)
+
     // Output:
     // 2006-01-02T23:04:05+08:00
 }
 ```
+
+
+### <span id="IsLeapYear">IsLeapYear</span>
+
+<p>check if param `year` is leap year or not.</p>
+
+<b>Signature:</b>
+
+```go
+func IsLeapYear(year int) bool
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datetime"
+)
+
+func main() {
+    result1 := datetime.IsLeapYear(2000)
+    result2 := datetime.IsLeapYear(2001)
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // true
+    // false
+}
+```