Add homeDir to Deno namespace (#2578)

3 files changed, 32 insertions, 2 deletions

diff --git a/js/deno.ts b/js/deno.ts
index 3275d9353..0bc3c95c7 100644
--- a/js/deno.ts
+++ b/js/deno.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 
 // Public deno module.
-export { noColor, pid, env, exit, isTTY, execPath } from "./os";
+export { noColor, pid, env, exit, isTTY, execPath, homeDir } from "./os";
 export { chdir, cwd } from "./dir";
 export {
   File,
diff --git a/js/os.ts b/js/os.ts
index 0af4098c5..558f47efd 100644
--- a/js/os.ts
+++ b/js/os.ts
@@ -130,3 +130,23 @@ export function start(source?: string): msg.StartRes {
 
   return startResMsg;
 }
+
+/**
+ * Returns the current user's home directory.
+ * Does not require elevated privileges.
+ */
+export function homeDir(): string {
+  const builder = flatbuffers.createBuilder();
+  const inner = msg.HomeDir.createHomeDir(builder);
+  const baseRes = sendSync(builder, msg.Any.HomeDir, inner)!;
+  assert(msg.Any.HomeDirRes === baseRes.innerType());
+  const res = new msg.HomeDirRes();
+  assert(baseRes.inner(res) != null);
+  const path = res.path();
+
+  if (!path) {
+    throw new Error("Could not get home directory.");
+  }
+
+  return path;
+}
diff --git a/js/os_test.ts b/js/os_test.ts
index d3c9e6546..766cd1c3f 100644
--- a/js/os_test.ts
+++ b/js/os_test.ts
@@ -1,5 +1,11 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-import { test, testPerm, assert, assertEquals } from "./test_util.ts";
+import {
+  test,
+  testPerm,
+  assert,
+  assertEquals,
+  assertNotEquals
+} from "./test_util.ts";
 
 testPerm({ env: true }, function envSuccess(): void {
   const env = Deno.env();
@@ -32,3 +38,7 @@ test(function osPid(): void {
 test(function osIsTTYSmoke(): void {
   console.log(Deno.isTTY());
 });
+
+test(function homeDir(): void {
+  assertNotEquals(Deno.homeDir(), "");
+});