Mix-format daemon

Questions / Help
1

Is there anyway to keep “mix format” running and watching files on a specific directory?

I tried to run it automatically whenever I save a file, but it takes some time and I’m that kind of dev that saves pretty much everytime. :stuck_out_tongue:

I might be wrong, but I feel that a great deal of the time it takes to format the file is related to starting mix up.

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2

I’m not aware of a daemon, but I do know that editors can take advantage of ElixirLS which is a server running in the background (like a daemon I suppose) and perform tasks like formatting your code. You can adjust settings in your editor to format on save or on-demand. Might be faster to use ElixirLS than spinning up mix to format each time.

Which editor do you use?

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3

The problem with that is that it would modify file twice. You can “hand craft” something like that by using entr(1), however I would say that you should use pre-save hook in your editor.

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4

Thanks, @dbern!

I’m using NeoVim, with coc-elixir using elixir-ls to lint and autocomplete my code. I didn’t know that elixir-ls could also handle code formatting.

5

So, turns out coc has a feature to run the format command offered by the language servers. Here’s how to do it:

1- Run the command :CocConfig
2- Add elixir to the following configuration:

{
  coc: {
     preferences : {
       "formatOnSaveFiletypes": ["html", "javascript", "elixir"]
     }
  }
}

You can also use :call CocAction('format') to format on demand.

Thanks again, @dbern and @hauleth!

6

Your client need to support the code format action.

I know nothing about which features are supported by coc.vim. You need to consult its documentation.

Or perhaps @hauleth can help you. I know he uses vim + elixir-ls, though I do not know which client he uses.

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7

Thanks, @NobbZ.

I was doing just that :slight_smile:

After I made the change formatting became instantaneous. mix format was taking more than a couple seconds sometimes.

8

Yep you got it. I do something really similar

My vim config has a lot of trash in it but feel free to peruse it to find other tips

9

Here’s what I’m using (auto format and re-run affected tests):

watchexec -e 'ex,exs,eex,leex' -- 'mix format && mix test --stale'

You need to configure your editor to properly pick up external changes automatically and not nag you with a popup.

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10

This worked brilliantly! Amazing! Thank you very much.

11

if you have a program like say or speak, you can do really fun stuff like:

ls **/*.{ex,exs,heex} | entr sh -c "mix format; mix test && say 'tests all green' || say 'we have a problem, some test failed'"
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