Add `nvm_add_iojs_prefix`

nvm.sh

@@ -358,6 +358,10 @@ nvm_is_iojs_version() {
   [ "_$(echo "$1" | cut -c1-5)" = "_iojs-" ]
 }
 
+nvm_add_iojs_prefix() {
+  command echo "$(nvm_iojs_prefix)-$(nvm_ensure_version_prefix "$(nvm_strip_iojs_prefix "$1")")"
+}
+
 nvm_strip_iojs_prefix() {
   local NVM_IOJS_PREFIX
   NVM_IOJS_PREFIX="$(nvm_iojs_prefix)"
@@ -1212,7 +1216,7 @@ nvm() {
     "unload" )
       unset -f nvm nvm_print_versions nvm_checksum \
         nvm_iojs_prefix nvm_node_prefix \
-        nvm_strip_iojs_prefix \
+        nvm_add_iojs_prefix nvm_strip_iojs_prefix \
         nvm_is_iojs_version \
         nvm_ls_remote nvm_ls nvm_remote_version \
         nvm_version nvm_rc_version \

test/fast/Unit tests/nvm_add_iojs_prefix

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+die () { echo $@ ; exit 1; }
+
+. ../../../nvm.sh
+
+[ "_$(nvm_add_iojs_prefix 1)" = "_iojs-v1" ] || die '"nvm_add_iojs_prefix 1" did not return "iojs-v1"'
+[ "_$(nvm_add_iojs_prefix iojs-1)" = "_iojs-v1" ] || die '"nvm_add_iojs_prefix iojs-1" did not return "iojs-v1"'
+[ "_$(nvm_add_iojs_prefix iojs-1.2.3)" = "_iojs-v1.2.3" ] || die '"nvm_add_iojs_prefix iojs-1.2.3" did not return "iojs-v1.2.3"'