diff --git a/javascript/net/grpc/web/grpc_generator.cc b/javascript/net/grpc/web/grpc_generator.cc
index 69772459..148ded18 100644
--- a/javascript/net/grpc/web/grpc_generator.cc
+++ b/javascript/net/grpc/web/grpc_generator.cc
@@ -734,13 +734,31 @@ void PrintTypescriptFile(Printer* printer, const FileDescriptor* file,
           printer->Outdent();
           printer->Print("}\n\n");
         } else {
+          printer->Print(vars, "$js_method_name$(\n");
+          printer->Indent();
+          printer->Print(vars,
+                         "request: $input_type$,\n"
+                         "metadata: grpcWeb.Metadata | null): Promise<$output_type$>;\n\n");
+          printer->Outdent();
+
           printer->Print(vars, "$js_method_name$(\n");
           printer->Indent();
           printer->Print(vars,
                          "request: $input_type$,\n"
                          "metadata: grpcWeb.Metadata | null,\n"
                          "callback: (err: grpcWeb.Error,\n"
+                         "           response: $output_type$) => void): grpcWeb.ClientReadableStream<$output_type$>;\n\n");
+          printer->Outdent();
+
+          printer->Print(vars, "$js_method_name$(\n");
+          printer->Indent();
+          printer->Print(vars,
+                         "request: $input_type$,\n"
+                         "metadata: grpcWeb.Metadata | null,\n"
+                         "callback?: (err: grpcWeb.Error,\n"
                          "           response: $output_type$) => void) {\n");
+          printer->Print(vars, "if (callback !== undefined) {\n");
+          printer->Indent();
           printer->Print(vars, "return this.client_.rpcCall(\n");
           printer->Indent();
           printer->Print(vars,
@@ -752,6 +770,16 @@ void PrintTypescriptFile(Printer* printer, const FileDescriptor* file,
                          "callback);\n");
           printer->Outdent();
           printer->Outdent();
+          printer->Print(vars,
+                         "}\n"
+                         "return this.client_.unaryCall(\n");
+          printer->Print(vars,
+                         "this.hostname_ +\n"
+                         "  '/$package_dot$$service_name$/$method_name$',\n"
+                         "request,\n"
+                         "metadata || {},\n"
+                         "this.methodInfo$method_name$);\n");
+          printer->Outdent();
           printer->Print("}\n\n");
         }
       }
diff --git a/packages/grpc-web/index.d.ts b/packages/grpc-web/index.d.ts
index 19126ef3..ca737ebc 100644
--- a/packages/grpc-web/index.d.ts
+++ b/packages/grpc-web/index.d.ts
@@ -11,6 +11,12 @@ declare module "grpc-web" {
   }
 
   export class AbstractClientBase {
+    unaryCall<Request, Response> (method: string,
+             request: Request,
+             metadata: Metadata,
+             methodInfo: AbstractClientBase.MethodInfo<Request, Response>
+            ): Promise<Response>;
+
     rpcCall<Request, Response> (method: string,
              request: Request,
              metadata: Metadata,