Add XO formatter for JavaScript

README.md

@@ -157,6 +157,10 @@ Here is a list of formatprograms that are supported by default, and thus will be
   It can be installed by running `npm install -g standard` (`nodejs` is required). No more configuration needed.
   More information about the style guide can be found here: http://standardjs.com/.
 
+* `xo` for __Javascript__.
+  It can be installed by running `npm install -g xo` (`nodejs` is required).
+  Here is the link to the repository: https://github.com/sindresorhus/xo.
+
 * `html-beautify` for __HTML__.
   It is shipped with `js-beautify`, which can be installed by running `npm install -g js-beautify`.
   Note that `nodejs` is needed for this to work.
@@ -307,6 +311,10 @@ contact me by creating an issue in this repository.
 
 ## Change log
 
+### January 2017
+
+* Add `xo` formatter for JavaScript.
+
 ### March 2016
 * Don't use the option formatprg internally anymore, to always have the possible of using the default `gq`
   command.

plugin/defaults.vim

@@ -156,12 +156,17 @@ if !exists('g:formatdef_standard_javascript')
     let g:formatdef_standard_javascript = '"standard --fix --stdin"'
 endif
 
+if !exists('g:formatdef_xo_javascript')
+    let g:formatdef_xo_javascript = '"xo --fix --stdin"'
+endif
+
 if !exists('g:formatters_javascript')
     let g:formatters_javascript = [
                 \ 'jsbeautify_javascript',
                 \ 'pyjsbeautify_javascript',
                 \ 'jscs',
-                \ 'standard_javascript'
+                \ 'standard_javascript',
+                \ 'xo_javascript'
                 \ ]
 endif