feat: added cron.WithSecondOptional()

Author: fufuok

README.md

@@ -5,13 +5,47 @@
 
 a cron library for go, optimized. 
 
-*forked from robfig/cron@Commits on Jan 6, 2021*
+*forked from robfig/cron/v3@Commits on Jan 6, 2021*
 
-## Merge pull request
+## ✨ Features
 
-- [feat: support overriding the Prev time for a new job/entry](https://github.com/robfig/cron/pull/446)
-- [Reduce LARGE CPU consumption by using min-heap instead of sorting all entries every time](https://github.com/robfig/cron/pull/423)
-- [add schedule.Prev()](https://github.com/robfig/cron/pull/361) 
+- Added `cron.WithSecondOptional()`
+- Support `WithRunImmediately()` option for job scheduling
+- Merge pull request
+  - [feat: support overriding the Prev time for a new job/entry](https://github.com/robfig/cron/pull/446)
+  - [Reduce LARGE CPU consumption by using min-heap instead of sorting all entries every time](https://github.com/robfig/cron/pull/423)
+  - [add schedule.Prev()](https://github.com/robfig/cron/pull/361) 
+
+## ⚡️ Quickstart
+
+```go
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/fufuok/cron"
+)
+
+func main() {
+	c := cron.New(cron.WithSecondOptional())
+	c.Start()
+	defer c.Stop()
+
+	id, _ := c.AddFunc(
+		"* * * * *",
+		func() { fmt.Println("Job.0s:", time.Now()) },
+		cron.WithRunImmediately(),
+	)
+	fmt.Println("Next:", c.Entry(id).Next, "Prev", c.Entry(id).Prev)
+
+	_, _ = c.AddFunc("* * * * * *", func() { fmt.Println("Job.s:", time.Now()) })
+	_, _ = c.AddFunc("1,20-40/5 * * * * *", func() { fmt.Println("Job/5:", time.Now()) })
+
+	time.Sleep(2 * time.Minute)
+}
+```
 
 ------
 

option.go

@@ -22,6 +22,15 @@ func WithSeconds() Option {
 	))
 }
 
+// WithSecondOptional overrides the parser used for interpreting job schedules to
+// include a seconds field as the first one.
+// The seconds field as the first is optional.
+func WithSecondOptional() Option {
+	return WithParser(NewParser(
+		SecondOptional | Minute | Hour | Dom | Month | Dow | Descriptor,
+	))
+}
+
 // WithParser overrides the parser used for interpreting job schedules.
 func WithParser(p ScheduleParser) Option {
 	return func(c *Cron) {

option_test.go

@@ -40,3 +40,22 @@ func TestWithVerboseLogger(t *testing.T) {
 		t.Error("expected to see some actions, got:", out)
 	}
 }
+
+func TestWithSecondOptional(t *testing.T) {
+	c := New(WithSecondOptional())
+	id1, err := c.AddFunc("5 * * * *", func() {})
+	if err != nil {
+		t.Errorf("add func %v", err)
+	}
+	id2, err := c.AddFunc("* 5 * * * *", func() {})
+	if err != nil {
+		t.Errorf("add func %v", err)
+	}
+	c.Start()
+	next1 := c.Entry(id1).Next
+	next2 := c.Entry(id2).Next
+	if next1 != next2 {
+		t.Errorf("expect the same execution time: %s, %s", next1, next2)
+	}
+	c.Stop()
+}