diff --git a/README.md b/README.md
index 0315bf2..190ee14 100644
--- a/README.md
+++ b/README.md
@@ -10,8 +10,9 @@
 * [ ] R2 - Partially supported
   - [x] Head
   - [x] Get
-  - [ ] Put
-  - [ ] Delete
+  - [x] Put (load all bytes to memory)
+  - [ ] Put (stream)
+  - [x] Delete
   - [x] List
   - [ ] Options for R2 methods
 * [ ] environment variables (WIP)
diff --git a/examples/r2-image-server/README.md b/examples/r2-image-server/README.md
index 8702731..78bd7d8 100644
--- a/examples/r2-image-server/README.md
+++ b/examples/r2-image-server/README.md
@@ -1,14 +1,26 @@
 # r2-image-server
 
-* An example server which returns image from Cloudflare R2.
-* This server is implemented in Go and compiled with tinygo.
+* An example server of R2.
+* This server can store / load / delete images in R2.
 
-## Example
+## Usage
 
-* https://r2-image-server.syumai.workers.dev/syumai.png
+### Endpoints
+
+* **GET `/images/{key}`**
+  - Get an image object at the `key` and returns it.
+* **POST `/images/{key}`**
+  - Create an image object at the `key` and uploads image.
+  - Request body must be binary and request header must have `Content-Type`.
+* **DELETE `/images/{key}`**
+  - Delete an image object at the `key`.
 
 ## Development
 
+* See the following documents for details on how to use R2.
+  - https://developers.cloudflare.com/r2/runtime-apis
+  - https://pkg.go.dev/github.com/syumai/workers
+
 ### Requirements
 
 This project requires these tools to be installed globally.
diff --git a/examples/r2-image-server/main.go b/examples/r2-image-server/main.go
index 0313a67..a6df295 100644
--- a/examples/r2-image-server/main.go
+++ b/examples/r2-image-server/main.go
@@ -5,6 +5,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"os"
 	"strings"
 
 	"github.com/syumai/workers"
@@ -16,26 +17,61 @@ const bucketName = "BUCKET"
 func handleErr(w http.ResponseWriter, msg string, err error) {
 	log.Println(err)
 	w.WriteHeader(http.StatusInternalServerError)
+	w.Header().Set("Content-Type", "text/plain")
 	w.Write([]byte(msg))
 }
 
-// This example is based on implementation in syumai/workers-playground
-// * https://github.com/syumai/workers-playground/blob/e32881648ccc055e3690a0d9c750a834261c333e/r2-image-viewer/src/index.ts#L30
-func handler(w http.ResponseWriter, req *http.Request) {
+type server struct {
+	bucket workers.R2Bucket
+}
+
+func newServer() (*server, error) {
+	// delete image object from R2
 	bucket, err := workers.NewR2Bucket(bucketName)
 	if err != nil {
-		handleErr(w, "failed to get R2Bucket\n", err)
+		return nil, err
+	}
+	return &server{bucket: bucket}, nil
+}
+
+func (s *server) post(w http.ResponseWriter, req *http.Request, key string) {
+	objects, err := s.bucket.List()
+	if err != nil {
+		handleErr(w, "failed to list R2Objects\n", err)
 		return
 	}
-	imgPath := strings.TrimPrefix(req.URL.Path, "/")
-	imgObj, err := bucket.Get(imgPath)
+	for _, obj := range objects.Objects {
+		if obj.Key == key {
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprintf(w, "key %s already exists\n", key)
+			return
+		}
+	}
+	_, err = s.bucket.Put(key, req.Body, &workers.R2PutOptions{
+		HTTPMetadata: workers.R2HTTPMetadata{
+			ContentType: req.Header.Get("Content-Type"),
+		},
+		CustomMetadata: map[string]string{"custom-key": "custom-value"},
+	})
+	if err != nil {
+		handleErr(w, "failed to put R2Object\n", err)
+		return
+	}
+	w.WriteHeader(http.StatusCreated)
+	w.Header().Set("Content-Type", "text/plain")
+	w.Write([]byte("successfully uploaded image"))
+}
+
+func (s *server) get(w http.ResponseWriter, req *http.Request, key string) {
+	// get image object from R2
+	imgObj, err := s.bucket.Get(key)
 	if err != nil {
 		handleErr(w, "failed to get R2Object\n", err)
 		return
 	}
 	if imgObj == nil {
 		w.WriteHeader(http.StatusNotFound)
-		w.Write([]byte(fmt.Sprintf("image not found: %s", imgPath)))
+		w.Write([]byte(fmt.Sprintf("image not found: %s", key)))
 		return
 	}
 	w.Header().Set("Cache-Control", "public, max-age=14400")
@@ -48,6 +84,40 @@ func handler(w http.ResponseWriter, req *http.Request) {
 	io.Copy(w, imgObj.Body)
 }
 
-func main() {
-	workers.Serve(http.HandlerFunc(handler))
+func (s *server) delete(w http.ResponseWriter, req *http.Request, key string) {
+	// delete image object from R2
+	if err := s.bucket.Delete(key); err != nil {
+		handleErr(w, "failed to delete R2Object\n", err)
+		return
+	}
+	w.Header().Set("Content-Type", "text/plain")
+	w.Write([]byte("successfully deleted image"))
+}
+
+func (s *server) routeHandler(w http.ResponseWriter, req *http.Request) {
+	key := strings.TrimPrefix(req.URL.Path, "/")
+	switch req.Method {
+	case "GET":
+		s.get(w, req, key)
+		return
+	case "DELETE":
+		s.delete(w, req, key)
+		return
+	case "POST":
+		s.post(w, req, key)
+		return
+	default:
+		w.WriteHeader(http.StatusNotFound)
+		w.Write([]byte("url not found\n"))
+		return
+	}
+}
+
+func main() {
+	s, err := newServer()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to start server: %v", err)
+		os.Exit(1)
+	}
+	workers.Serve(http.HandlerFunc(s.routeHandler))
 }
diff --git a/jsutil.go b/jsutil.go
index e84b891..6affd51 100644
--- a/jsutil.go
+++ b/jsutil.go
@@ -2,7 +2,6 @@ package workers
 
 import (
 	"fmt"
-	"strconv"
 	"syscall/js"
 	"time"
 )
@@ -17,9 +16,7 @@ var (
 	uint8ArrayClass     = global.Get("Uint8Array")
 	errorClass          = global.Get("Error")
 	readableStreamClass = global.Get("ReadableStream")
-	stringClass         = global.Get("String")
 	dateClass           = global.Get("Date")
-	numberClass         = global.Get("Number")
 )
 
 func newObject() js.Value {
@@ -96,16 +93,11 @@ func maybeDate(v js.Value) (time.Time, error) {
 
 // dateToTime converts JavaScript side's Data object into time.Time.
 func dateToTime(v js.Value) (time.Time, error) {
-	milliStr := stringClass.Invoke(v.Call("getTime")).String()
-	milli, err := strconv.ParseInt(milliStr, 10, 64)
-	if err != nil {
-		return time.Time{}, fmt.Errorf("failed to convert Date to time.Time: %w", err)
-	}
-	return time.UnixMilli(milli), nil
+	milli := v.Call("getTime").Float()
+	return time.UnixMilli(int64(milli)), nil
 }
 
 // timeToDate converts Go side's time.Time into Date object.
 func timeToDate(t time.Time) js.Value {
-	milliStr := strconv.FormatInt(t.UnixMilli(), 10)
-	return dateClass.New(numberClass.Call(milliStr))
+	return dateClass.New(t.UnixMilli())
 }
diff --git a/r2bucket.go b/r2bucket.go
index d379c8c..1fbc6b5 100644
--- a/r2bucket.go
+++ b/r2bucket.go
@@ -99,11 +99,24 @@ func (opts *R2PutOptions) toJS() js.Value {
 }
 
 // Put returns the result of `put` call to R2Bucket.
+// * This method copies all bytes into memory for implementation restriction.
 // * Body field of *R2Object is always nil for Put call.
 // * if a network error happens, returns error.
 func (r *r2Bucket) Put(key string, value io.ReadCloser, opts *R2PutOptions) (*R2Object, error) {
+	/* TODO: implement this in FixedLengthStream: https://developers.cloudflare.com/workers/runtime-apis/streams/transformstream/#fixedlengthstream
 	body := convertReaderToReadableStream(value)
-	p := r.instance.Call("put", key, body, opts.toJS())
+	streams := fixedLengthStreamClass.New(contentLength)
+	rs := streams.Get("readable")
+	body.Call("pipeTo", streams.Get("writable"))
+	*/
+	b, err := io.ReadAll(value)
+	if err != nil {
+		return nil, err
+	}
+	defer value.Close()
+	ua := newUint8Array(len(b))
+	js.CopyBytesToJS(ua, b)
+	p := r.instance.Call("put", key, ua.Get("buffer"), opts.toJS())
 	v, err := awaitPromise(p)
 	if err != nil {
 		return nil, err
diff --git a/r2objects.go b/r2objects.go
index df14f8a..e812429 100644
--- a/r2objects.go
+++ b/r2objects.go
@@ -28,15 +28,15 @@ func toR2Objects(v js.Value) (*R2Objects, error) {
 		}
 		objects[i] = obj
 	}
-	prefixesVal := objectsVal.Get("delimitedPrefixes")
+	prefixesVal := v.Get("delimitedPrefixes")
 	prefixes := make([]string, prefixesVal.Length())
 	for i := 0; i < len(prefixes); i++ {
 		prefixes[i] = prefixesVal.Index(i).String()
 	}
 	return &R2Objects{
 		Objects:           objects,
-		Truncated:         objectsVal.Get("truncated").Bool(),
-		Cursor:            maybeString(objectsVal.Get("cursor")),
+		Truncated:         v.Get("truncated").Bool(),
+		Cursor:            maybeString(v.Get("cursor")),
 		DelimitedPrefixes: prefixes,
 	}, nil
 }