From 0ccae77ce2b0291d42f79f7182f8378cddce05d4 Mon Sep 17 00:00:00 2001
From: Luke Childs <lukechilds123@gmail.com>
Date: Sun, 31 Jul 2016 20:15:06 +0100
Subject: [PATCH] Do proper empty string test rather than truthy

Truthy doesn't seem to work on older versions of zsh
5.0.2 fails, 5.1 works
---
 zsh-nvm.plugin.zsh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/zsh-nvm.plugin.zsh b/zsh-nvm.plugin.zsh
index c166722..14f0574 100644
--- a/zsh-nvm.plugin.zsh
+++ b/zsh-nvm.plugin.zsh
@@ -62,7 +62,7 @@ nvm_update() {
 _zsh_nvm_upgrade() {
 
   # Use default upgrade if it's built in
-  if [[ "$(_zsh_nvm_nvm help | grep 'nvm upgrade')" ]]; then
+  if [[ -n "$(_zsh_nvm_nvm help | grep 'nvm upgrade')" ]]; then
     _zsh_nvm_nvm upgrade
     return
   fi
@@ -88,7 +88,7 @@ _zsh_nvm_previous_version() {
 
 _zsh_nvm_revert() {
   local previous_version="$(_zsh_nvm_previous_version)"
-  if [[ $previous_version ]]; then
+  if [[ -n "$previous_version" ]]; then
     local installed_version=$(cd "$NVM_DIR" && git describe --tags)
     if [[ "$installed_version" = "$previous_version" ]]; then
       echo "Already reverted to $installed_version"