Neomake hanging when using eslint

Question

I have been following the following two tutorials to try and set up eslint and Neomake:

• Linting code with Neomake and Neovim
• Linting code with Neovim and Neomake - ESLint edition

So I have the following minimal init.vim

call plug#begin('~/.vim/plugged')

Plug 'neomake/neomake'

call plug#end()

autocmd! BufWritePost,BufEnter * Neomake
let g:neomake_verbose=3
let g:neomake_open_list = 2
let g:neomake_javascript_enabled_makers = ['eslint']

" neomake
nmap <Leader><Space>o :lopen<CR>      " open location window
nmap <Leader><Space>c :lclose<CR>     " close location window
nmap <Leader><Space>, :ll<CR>         " go to current error/warning
nmap <Leader><Space>n :lnext<CR>      " next error/warning
nmap <Leader><Space>p :lprev<CR>      " previous error/warning

The problem is when I save Neomake hangs with the following message:

Neomake: Starting: eslint -f compact /home/otis/Developer/test/index.js

If i run that command manually outside of nvim like so:

eslint -f compact /home/otis/Developer/test/index.js

I receive the following output:

/home/otis/Developer/test/index.js: line 1, col 1, Error - Unexpected var, use let or const instead. (no-var)
/home/otis/Developer/test/index.js: line 1, col 5, Error - 'a' is defined but never used. (no-unused-vars)
/home/otis/Developer/test/index.js: line 1, col 9, Error - Strings must use singlequote. (quotes)

3 problems

Which is good it means eslint is working but I am getting nothing back from Neomake.

If I run :lopen the window pops up and then instantly closes like below:

My vim/nvim knowledge is somewhat basic so please be explicit in responses.

Answer 1

Some [lightly edited] info from the comments:

Actually this might be the reason for empty Quickfix window. On your screen cast when you run :lopen, Neomake runs for that buffer due to the autocmd for BufEnter. It should be additionally limited to JavaScript files only:

augroup neomake
  au!
  autocmd BufWritePost *.js Neomake
augroup END

Answer 2

This doesn't exactly answer your question, but I found that neomake works better with eslint_d. It has the nice side effect that it should do the linting faster too.

You first have to install eslint_d globally (but it still seems to pick up any local .eslintrc file):

npm install -g eslint_d

Then add the following configuration for neomake to your init.vim / .vimrc:

let g:neomake_javascript_enabled_makers = ['eslint_d']

For me that was all I required, after restarting neovim and opening a javascript file running :Neomake gave me eslint warnings.