Close Multiple Windows In A Neovim Plugin Via The API

### Overview

Took me some time (and help from folks on the OnlyDevs](https://www.twitch.tv/team/onlydevs) discord) to figure out how to close multiple floating windows with `:q` in a neovim plugin. The method I landed on is setting up the [WinClosed autocommand to trigger a function that closes the rest of the windows.

### Code

Here's an example:

__File: ~/.config/nvim/plugin/winclosed_multiple.vim__

Code

if exists('g:loaded_winclosed_multiple') | finish | endif

let s:save_cpo = &cpo
set cpo&vim

command! WinClosedMultiple lua require'winclosed_multiple'.winclosed_multiple()

let &cpo = s:save_cpo
unlet s:save_cpo

let g:loaded_winclosed_multiple = 1

__File: ~/.config/nvim/lua/winclosed_multiple.lua__

Code

local function close_windows()
    vim.api.nvim_buf_delete(buffer1, {})
    vim.api.nvim_buf_delete(buffer2, {})
    vim.api.nvim_buf_delete(buffer3, {})
    vim.api.nvim_buf_delete(buffer4, {})
end

local function winclosed_multiple()
    buffer1 = vim.api.nvim_create_buf(false, true)
    window1 = vim.api.nvim_open_win(buffer1, true, {
            style="minimal", relative='editor',
            row=3, col=3, width=10, height=6, border='single'
        }
    )
    buffer2 = vim.api.nvim_create_buf(false, true)
    window2 = vim.api.nvim_open_win(buffer2, true, {
            style="minimal", relative='editor',
            row=3, col=16, width=10, height=6, border='single'
        }
    )
    buffer3 = vim.api.nvim_create_buf(false, true)
    window3 = vim.api.nvim_open_win(buffer3, true, {
            style="minimal", relative='editor',
            row=3, col=29, width=10, height=6, border='single'
        }
    )
    buffer4 = vim.api.nvim_create_buf(false, true)
    window4 = vim.api.nvim_open_win(buffer4, true, {
            style="minimal", relative='editor',
            row=3, col=42, width=10, height=6, border='single'
        }
    )
    vim.api.nvim_command(
        'au WinClosed <buffer='..buffer1..'> lua require"winclosed_multiple".close_windows()'
    )
    vim.api.nvim_command(
        'au WinClosed <buffer='..buffer2..'> lua require"winclosed_multiple".close_windows()'
    )
    vim.api.nvim_command(
        'au WinClosed <buffer='..buffer3..'> lua require"winclosed_multiple".close_windows()'
    )
    vim.api.nvim_command(
        'au WinClosed <buffer='..buffer4..'> lua require"winclosed_multiple".close_windows()'
    )
end

return {
    winclosed_multiple = winclosed_multiple,
    close_windows = close_windows
}

### Details

- I'm not sure what the right way to install test plugins is, but dropping the files in the locations listed above worked for me - Call `:WinClosedMultiple` to run the example. It'll open four small windows that each have their own buffer - You can jump around with windows with `CTRL+W` then `W` - Closing any one of the small windows will close the remaining windows as well - Instead of using vim.api.nvim_buf_delete()`](https://neovim.io/doc/user/api.html#nvim_buf_delete()) you can also use [vim.api.nvim_win_close() if you want to leave the buffers open