diff --git a/cloudfirestore/convertible_batch_getter.go b/cloudfirestore/convertible_batch_getter.go
index 2edeabc..0d62351 100644
--- a/cloudfirestore/convertible_batch_getter.go
+++ b/cloudfirestore/convertible_batch_getter.go
@@ -1,7 +1,12 @@
 package cloudfirestore
 
-import "context"
+import (
+	"context"
 
+	"cloud.google.com/go/firestore"
+)
+
+type FuncGetDoc func(ids ...string) *firestore.DocumentRef
 type FuncGetID[D any] func(*D) string
 type FuncConvert[S, D any] func(*S) *D
 type ConvertibleBatchGetterItem[D any] interface {
diff --git a/cloudfirestore/typed_batch_getter.go b/cloudfirestore/typed_batch_getter.go
index 7646e53..b951c70 100644
--- a/cloudfirestore/typed_batch_getter.go
+++ b/cloudfirestore/typed_batch_getter.go
@@ -1,17 +1,5 @@
 package cloudfirestore
 
-import (
-	"context"
-
-	"cloud.google.com/go/firestore"
-)
-
-type FuncGetDoc func(ids ...string) *firestore.DocumentRef
-
 type TypedBatchGetter[T any] interface {
-	Add(ids ...string)
-	Delete(ids ...string)
-	GetMap() map[string]*T
-	Get(ids ...string) *T
-	Commit(ctx context.Context) error
+	ConvertibleBatchGetter[T, T]
 }
diff --git a/cloudfirestore/typed_batch_getter_impl.go b/cloudfirestore/typed_batch_getter_impl.go
index 0713d39..fe2ab4f 100644
--- a/cloudfirestore/typed_batch_getter_impl.go
+++ b/cloudfirestore/typed_batch_getter_impl.go
@@ -1,19 +1,32 @@
 package cloudfirestore
 
-import "context"
+func NewTypedBatchGetter[T any](
+	bg BatchGetter,
+	getDoc FuncGetDoc,
+	getID FuncGetID[T],
+	convert FuncConvert[T, T],
+) TypedBatchGetter[T] {
+	if convert == nil {
+		convert = func(t *T) *T { return t }
+	}
+	cbg := &convertibleBatchGetter[T, T]{
+		bg:      bg,
+		dstMap:  map[string]*T{},
+		items:   []*convertibleBatchGetterItem[*T]{},
+		getDoc:  getDoc,
+		getID:   getID,
+		convert: convert,
+	}
 
-type typedBatchGetter[T any] struct {
-	bg     BatchGetter
-	docMap map[string]string
-	getDoc FuncGetDoc
-}
+	bg.OnCommit(func() {
+		cbg.convertAll()
+	})
 
-func NewTypedBatchGetter[T any](bg BatchGetter, getDoc FuncGetDoc) TypedBatchGetter[T] {
-	return &typedBatchGetter[T]{
-		bg:     bg,
-		docMap: map[string]string{},
-		getDoc: getDoc,
-	}
+	bg.OnEnd(func() {
+		cbg.convertAll()
+	})
+
+	return cbg
 }
 
 type FuncGetModel[E, M any] func(e *E) (id string, m *M)
@@ -32,37 +45,3 @@ func GetModelMapByBatchGetter[E, M any](
 	}
 	return ms
 }
-
-func (tbg *typedBatchGetter[T]) Add(ids ...string) {
-	docRef := tbg.getDoc(ids...)
-	tbg.docMap[docRef.Path] = docRef.ID
-	data := new(T)
-	tbg.bg.Add(docRef, data)
-}
-
-func (tbg *typedBatchGetter[T]) Delete(ids ...string) {
-	docRef := tbg.getDoc(ids...)
-	delete(tbg.docMap, docRef.Path)
-	tbg.bg.Delete(docRef)
-}
-
-func (tbg *typedBatchGetter[T]) GetMap() map[string]*T {
-	m := map[string]*T{}
-	for k, id := range tbg.docMap {
-		d := tbg.bg.Get(k)
-		if d != nil {
-			m[id] = d.(*T)
-		}
-	}
-	return m
-}
-
-func (tbg *typedBatchGetter[T]) Get(ids ...string) *T {
-	docRef := tbg.getDoc(ids...)
-	data := tbg.bg.Get(docRef.Path)
-	return data.(*T)
-}
-
-func (tbg *typedBatchGetter[T]) Commit(ctx context.Context) error {
-	return tbg.bg.Commit(ctx)
-}