From 3243f7a08272a5f973a92fec781589e98f9f47b7 Mon Sep 17 00:00:00 2001
From: "Brandon L. Reiss" <brandon@frame.ai>
Date: Wed, 27 Jan 2021 13:12:17 -0500
Subject: [PATCH] [Fix] Fix potential unbound var error on nvm install

Fixes #2420. When using `nvm install` with an already installed
version, Bash (and potentially other shells) may emit an unbound
variable error when `set -u` is set. The presence of the error depends
on specific shell versions, but appears to happen in MacOS 11.1 (Big
Sur) using a recent Bash version installed via Homebrew (as of this
writing).

The fix accesses `ALIAS` correctly for the case where it is not set by
an `alias` option to `nvm install`.
---
 nvm.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nvm.sh b/nvm.sh
index 8d57caea74..e0eccfe412 100644
--- a/nvm.sh
+++ b/nvm.sh
@@ -3078,7 +3078,7 @@ nvm() {
           nvm_ensure_default_set "${provided_version}"
         fi
 
-        if [ -n "${ALIAS}" ]; then
+        if [ -n "${ALIAS-}" ]; then
           nvm alias "${ALIAS}" "${provided_version}"
         fi