Implement deno.readFile()

As an example of how to implement ops that have both sync and async
versions.

1 files changed, 34 insertions, 0 deletions

diff --git a/js/read_file_test.ts b/js/read_file_test.ts
new file mode 100644
index 000000000..6d4f71b62
--- /dev/null
+++ b/js/read_file_test.ts
@@ -0,0 +1,34 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import { test, assert, assertEqual } from "./test_util.ts";
+import * as deno from "deno";
+
+test(function readFileSyncSuccess() {
+  const data = deno.readFileSync("package.json");
+  assert(data.byteLength > 0);
+  const decoder = new TextDecoder("utf-8");
+  const json = decoder.decode(data);
+  const pkg = JSON.parse(json);
+  assertEqual(pkg.name, "deno");
+});
+
+test(function readFileSyncNotFound() {
+  let caughtError = false;
+  let data;
+  try {
+    data = deno.readFileSync("bad_filename");
+  } catch (e) {
+    caughtError = true;
+    assertEqual(e.kind, deno.ErrorKind.NotFound);
+  }
+  assert(caughtError);
+  assert(data === undefined);
+});
+
+test(async function readFileSuccess() {
+  const data = await deno.readFile("package.json");
+  assert(data.byteLength > 0);
+  const decoder = new TextDecoder("utf-8");
+  const json = decoder.decode(data);
+  const pkg = JSON.parse(json);
+  assertEqual(pkg.name, "deno");
+});