How to pass argument to Neoformat for prettier-eslint-cli from a variable in vimrc

Question

I have the following line of code:

  autocmd FileType javascript execute "setlocal formatprg=".g:prettier_eslint_path2."\\ --eslint-config-path" . g:eslintrc_full_path ."\\"

I can see this when I start vim in the directory which has .eslintrc:

ESLINTRC PATH
.eslintrc
Prettier ESLINT PATH
/Users/localuser/lendi/lendi-app/node_modules/.bin/prettier-eslint^@
/Users/localuser/lendi/lendi-app/node_modules/.bin/prettier-eslint
Has  ESLINTRC
/Users/localuser/lendi/lendi-app/.eslintrc
--- Auto-Commands ---
Press ENTER or type command to continue

I have the g:eslintrc_full_path logged out correctly, how do I pass it from the variable to formatprg correctly.

If I remove the args, I get an empty output as the result of the file.

If I remove the \\ it informs that it is valid to do so.

I dont understand how to pass arguments to the cli script when using a variable. I did not find any examples of string interpolation when reading through http://learnvimscriptthehardway.stevelosh.com/chapters/26.html

Also, the following code also causes a problem:

  autocmd FileType javascript execute "setlocal formatprg=".g:prettier_eslint_path2."\\ --eslint-config-path\\ ".g:eslintrc_full_path

and deletes the entire file. I have tried:

  autocmd FileType javascript execute "setlocal formatprg=".g:prettier_eslint_path2."\\ --eslint-config-path\\ ".g:eslintrc_full_path

but it deletes the contents of the file as well.

I have tried it with only --stdin like this but it fails and converts everything to double quotes:

  autocmd FileType javascript execute "setlocal formatprg=".g:prettier_eslint_path2."\\ --stdin"

I have tried adding in the single quote as an argument here but it still converts everything to double-quotes.

autocmd FileType javascript let &l:formatprg= g:prettier_eslint_path2."\\ --single-quote\\ --eslint-config-path\\ ". g:eslintrc_full_path

Also, logging &l:formatprg does not work:

autocmd FileType javascript let &l:formatprg = g:prettier_eslint_path2.' --single-quote --eslint-config-path '. g:eslintrc_full_path
echom &l:formatprg

I tried checking the messages:

and it shows:

/Users/localuser/lendi/lendi-app/node_modules/.bin/prettier-eslint --single-quote --write --eslint-config-path /Users/localuser/lendi/lendi-app/.eslintrc

which should work. How does neoformat pass the file to the cli script.

How do I solve this problem?

I have also created a issue on neoformat for the same:

https://github.com/sbdchd/neoformat/issues/112

Answer 1

Maybe this is an escaping problem, you should use:

autocmd FileType javascript setlocal formatprg=command\ --arg

Or if you need variables:

autocmd FileType javascript let &l:formatprg = 'command ' . l:arg

---

Update: As commented by the plugin owner, it would be easier to define a formatter via Neoformat:

let g:neoformat_javascript_eslint = {
            \ 'exe': 'eslint',
            \ 'args': [],
            \ }

let g:neoformat_enabled_javascript = ['eslint']

But if you want to keep using formatprg, you should get rid of the FileType auto command and put setlocal {option} or let &l:{option} directly in ftplugin/javascript.vim, see :help filetype-plugin.

Answer 2

When using the formatprg option, Vim passes the file contents to the external program on stdin. (See :help 'formatprg')

You are not telling prettier-eslint-cli to expect to receive input in this way, and so the command fails.

The README for prettier-eslint-cli explains how to use it from Vim:

Vim users can add the following to their .vimrc:

autocmd FileType javascript set formatprg=prettier-eslint\ --stdin

(Emphasis mine)

You also want to specify the paths of the executable and rcfile, so you need to amend this to add these in, whilst continuing to pass the necessary --stdin option.

autocmd FileType javascript let &l:formatprg = g:prettier_eslint_path2.' --stdin --eslint-config-path '. g:eslintrc_full_path