Show NodeJS version in Powerline themes (#1438)

Currently, only nvm is supported.

themes/powerline/README.md

@@ -56,6 +56,7 @@ The contents of the prompt can be "reordered", all the "segments" (every piece o
 * `python_venv` - Python virtual environment information (`virtualenv`, `venv`
   and `conda` supported)
 * `ruby` - Current ruby version if using `rvm`
+* `node` - Current node version (only `nvm` is supported)
 * `scm` - Version control information, `git`
 * `user_info` - Current user
 * `wd` - Working directory, like `cwd` but doesn't show the full folder

themes/powerline/powerline.base.bash

@@ -40,6 +40,13 @@ function __powerline_user_info_prompt {
   [[ -n "${user_info}" ]] && echo "${user_info}|${color}"
 }
 
+function __powerline_node_prompt {
+  local node_version=""
+
+  node_version="$(node_version_prompt)"
+  [[ -n "${node_version}" ]] && echo "${NODE_CHAR}${node_version}|${NODE_THEME_PROMPT_COLOR}"
+}
+
 function __powerline_ruby_prompt {
   local ruby_version=""
 

themes/powerline/powerline.theme.bash

@@ -24,6 +24,11 @@ SCM_THEME_PROMPT_STAGED_COLOR=30
 SCM_THEME_PROMPT_UNSTAGED_COLOR=92
 SCM_THEME_PROMPT_COLOR=${SCM_THEME_PROMPT_CLEAN_COLOR}
 
+NVM_THEME_PROMPT_PREFIX=""
+NVM_THEME_PROMPT_SUFFIX=""
+NODE_CHAR=${POWERLINE_NODE_CHAR:="❲n❳ "}
+NODE_THEME_PROMPT_COLOR=22
+
 RVM_THEME_PROMPT_PREFIX=""
 RVM_THEME_PROMPT_SUFFIX=""
 RBENV_THEME_PROMPT_PREFIX=""
@@ -55,7 +60,7 @@ IN_VIM_THEME_PROMPT_TEXT="vim"
 
 HOST_THEME_PROMPT_COLOR=0
 
-POWERLINE_PROMPT=${POWERLINE_PROMPT:="user_info scm python_venv ruby cwd"}
+POWERLINE_PROMPT=${POWERLINE_PROMPT:="user_info scm python_venv ruby node cwd"}
 
 HISTORY_AUTOSAVE=${HISTORY_AUTOSAVE:-0}