Add optional debounce parameter

go.mod

@@ -3,6 +3,7 @@ module github.com/romshark/watchserve
 go 1.16
 
 require (
+	github.com/bep/debounce v1.2.0
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/pkg/browser v0.0.0-20210606212950-a7b7a6107d32
 	github.com/r3labs/sse/v2 v2.3.3

go.sum

@@ -1,3 +1,5 @@
+github.com/bep/debounce v1.2.0 h1:wXds8Kq8qRfwAOpAxHrJDbCXgC5aHSzgQb/0gKsHQqo=
+github.com/bep/debounce v1.2.0/go.mod h1:H8yggRPQKLUhUoqrJC1bO2xNya7vanpDl7xR3ISbCJ0=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=

serve.go

@@ -7,9 +7,11 @@ import (
 	"net/http"
 	"os"
 	"sync"
+	"time"
 
 	_ "embed"
 
+	"github.com/bep/debounce"
 	"github.com/fsnotify/fsnotify"
 	"github.com/pkg/browser"
 	sse "github.com/r3labs/sse/v2"
@@ -21,6 +23,7 @@ var frameHTML []byte
 func main() {
 	fFilePath := flag.String("f", "", "file path")
 	fHost := flag.String("host", "127.0.0.1:8080", "host address")
+	fDebounce := flag.Duration("debounce", 0, "debounce duration")
 	flag.Parse()
 
 	if *fFilePath == "" {
@@ -39,7 +42,7 @@ func main() {
 	var wg sync.WaitGroup
 	wg.Add(1)
 
-	go watchFile(*fFilePath, sseSrv, "updates")
+	go watchFile(*fFilePath, sseSrv, "updates", *fDebounce)
 	go listenHTTP(*fHost, *fFilePath, fileContents, sseSrv)
 
 	{
@@ -57,6 +60,7 @@ func watchFile(
 	filePath string,
 	sseSrv *sse.Server,
 	streamUpdates string,
+	debounceDur time.Duration,
 ) {
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
@@ -68,16 +72,22 @@ func watchFile(
 	}
 
 	var updateMsgWrite = []byte("write")
+	publishEvent := func() {
+		sseSrv.Publish(streamUpdates, &sse.Event{
+			Data: updateMsgWrite,
+		})
+	}
+
+	debounced := debounce.New(debounceDur)
+
 	for {
 		select {
 		case e := <-watcher.Events:
 			if e.Name != filePath || e.Op == fsnotify.Write {
 				continue
 			}
 			log.Print("file change detected")
-			sseSrv.Publish(streamUpdates, &sse.Event{
-				Data: updateMsgWrite,
-			})
+			debounced(publishEvent)
 		case err := <-watcher.Errors:
 			log.Fatal("watching file:", err)
 		}