Add userHomeDir (denoland/deno_std#521)

Original: https://github.com/denoland/deno_std/commit/ff7fb5a5d696256b232f8435c53087d5b12848ab

1 files changed, 26 insertions, 0 deletions

diff --git a/os/mod.ts b/os/mod.ts
new file mode 100644
index 000000000..a2bb0457b
--- /dev/null
+++ b/os/mod.ts
@@ -0,0 +1,26 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+/**
+ * Returns the current user's home directory.
+ * On Unix, including macOS, it returns the $HOME environment variable.
+ * On Windows, it returns %USERPROFILE%.
+ * Needs permissions to access env (--allow-env).
+ *
+ * Ported from Go: https://github.com/golang/go/blob/go1.12.5/src/os/file.go#L389
+ */
+export function userHomeDir(): string {
+  let env = "HOME";
+  let envErr = "$HOME";
+
+  if (Deno.platform.os === "win") {
+    env = "USERPROFILE";
+    envErr = "%USERPROFILE%";
+  }
+
+  const value = Deno.env()[env];
+  if (value !== "") {
+    return value;
+  }
+
+  throw new Error(`Environment variable '${envErr}' is not defined.`);
+}