diff --git a/main.go b/main.go
index 3ee79fb6bd..4612849db0 100644
--- a/main.go
+++ b/main.go
@@ -3,12 +3,37 @@ package main
 import (
 	"github.com/golang/protobuf/proto"
 	"github.com/ry/v8worker2"
+	"io/ioutil"
 	"os"
 )
 
-func recv(msg []byte) []byte {
-	println("recv cb", string(msg))
-	return nil
+func ReadFileSync(filename string) []byte {
+	buf, err := ioutil.ReadFile(filename)
+	msg := &Msg{Kind: Msg_DATA_RESPONSE}
+	if err != nil {
+		msg.Error = err.Error()
+	} else {
+		msg.Data = buf
+	}
+	out, err := proto.Marshal(msg)
+	if err != nil {
+		panic(err)
+	}
+	return out
+}
+
+func recv(buf []byte) []byte {
+	msg := &Msg{}
+	err := proto.Unmarshal(buf, msg)
+	if err != nil {
+		panic(err)
+	}
+	switch msg.Kind {
+	case Msg_READ_FILE_SYNC:
+		return ReadFileSync(msg.Path)
+	default:
+		panic("Unexpected message")
+	}
 }
 
 func loadAsset(w *v8worker2.Worker, path string) {
diff --git a/main.ts b/main.ts
index 153414a195..3a6a043aba 100644
--- a/main.ts
+++ b/main.ts
@@ -1,10 +1,29 @@
 //import * as ts from "typescript";
 import { main as pb } from "./msg.pb"
 import "./util";
+import { TextDecoder } from "text-encoding";
 
+function readFileSync(filename: string): string {
+  const msg = pb.Msg.fromObject({
+    kind: pb.Msg.MsgKind.READ_FILE_SYNC,
+    path: filename
+  });
+  const ui8 = pb.Msg.encode(msg).finish();
+  const ab = ui8.buffer.slice(ui8.byteOffset, ui8.byteOffset + ui8.byteLength);
+  const resBuf = V8Worker2.send(ab as ArrayBuffer);
+  const res = pb.Msg.decode(new Uint8Array(resBuf));
+  if (res.error != null && res.error.length > 0) {
+    throw Error(res.error);
+  }
+  const decoder = new TextDecoder("utf8");
+  return decoder.decode(res.data)
+}
 
 function load(argv: string[]): void {
   console.log("Load argv", argv);
+  const inputFn = argv[1];
+  const source = readFileSync(inputFn);
+  console.log("source", source)
 }
 
 V8Worker2.recv((ab: ArrayBuffer) => {
diff --git a/msg.proto b/msg.proto
index d76875e130..00598ea903 100644
--- a/msg.proto
+++ b/msg.proto
@@ -5,9 +5,18 @@ package main;
 message Msg {
   enum MsgKind {
     LOAD = 0;
+    READ_FILE_SYNC = 1;
+    DATA_RESPONSE = 2;
   }
   MsgKind kind = 10;
 
   // LOAD
 	repeated string argv = 11;
+
+  // READ_FILE_SYNC
+	string path = 12;
+
+  // DATA_RESPONSE
+	bytes data = 13;
+  string error = 14;
 }
diff --git a/package.json b/package.json
index 6b011d247a..a4f93d7740 100644
--- a/package.json
+++ b/package.json
@@ -1,8 +1,10 @@
 {
   "name": "deno",
   "devDependencies": {
+    "@types/text-encoding": "^0.0.32",
     "parcel-bundler": "^1.8.1",
     "protobufjs": "^6.8.6",
+    "text-encoding": "^0.6.4",
     "typescript": "^2.8.3"
   }
 }
diff --git a/testdata/hello_world.js b/testdata/hello_world.js
new file mode 100644
index 0000000000..accefceba6
--- /dev/null
+++ b/testdata/hello_world.js
@@ -0,0 +1 @@
+console.log("Hello World");
diff --git a/testdata/hello_world.out b/testdata/hello_world.out
new file mode 100644
index 0000000000..557db03de9
--- /dev/null
+++ b/testdata/hello_world.out
@@ -0,0 +1 @@
+Hello World
diff --git a/tsconfig.json b/tsconfig.json
index d0810f8301..71fb930b73 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,8 +7,8 @@
     "removeComments": true,
     "preserveConstEnums": true,
     "declaration": true,
-    "target": "es5",
-    "lib": ["es2015"],
+    "target": "es2017",
+    "lib": ["es2017"],
     "noEmit": true,
     "noUnusedLocals": true,
     "noImplicitReturns": true,
diff --git a/yarn.lock b/yarn.lock
index c0027a0785..d6e4f1bfa0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -53,6 +53,10 @@
   version "8.10.14"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-8.10.14.tgz#a24767cfa22023f1bf7e751c0ead56a14c07ed45"
 
+"@types/text-encoding@^0.0.32":
+  version "0.0.32"
+  resolved "https://registry.yarnpkg.com/@types/text-encoding/-/text-encoding-0.0.32.tgz#52289b320a406850b14f08f48b475ca021218048"
+
 abbrev@1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
@@ -3388,6 +3392,10 @@ tar@^4:
     safe-buffer "^5.1.2"
     yallist "^3.0.2"
 
+text-encoding@^0.6.4:
+  version "0.6.4"
+  resolved "https://registry.yarnpkg.com/text-encoding/-/text-encoding-0.6.4.tgz#e399a982257a276dae428bb92845cb71bdc26d19"
+
 through2@^2.0.0, through2@~2.0.3:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/through2/-/through2-2.0.3.tgz#0004569b37c7c74ba39c43f3ced78d1ad94140be"