NeoVim

Use Appearance for NeoVim.

First of all you will of course need to have NeoVim installed. But you also need to install NeoVim Remote for this script to work.

Copy and paste the following content to a file at ~/.config/appearance/hooks/neovim.

#!/usr/bin/env bash

set -exuo pipefail

NEOVIM_REMOTE="/usr/local/bin/nvr"

if ! command -v $NEOVIM_REMOTE &> /dev/null
then
  echo "Command \"nvr\" could not be found"
  echo "Install using: \"pip3 install neovim-remote\" or read more at https://github.com/mhinz/neovim-remote"
  exit 1
fi

for server in $($NEOVIM_REMOTE --serverlist)
do
  if [ "$1" == "Dark" ]; then
    $NEOVIM_REMOTE --servername $server -cc ":call DarkMode()"
  else
    $NEOVIM_REMOTE --servername $server -cc ":call LightMode()"
  fi
done

Make it executable by running chmod u+x ~/.config/appearance/hooks/neovim.

The hook will call on the function DarkMode when macOS enters dark mode and LightMode when macOS enters light mode. So we need to implement those methods as well for NeoVim. So edit your .vimrc or init.vim file and add those methods by copy and paste the content below. This will also make sure that NeoVim always starts with the correct colorscheme.

function! DarkMode()
  set background=dark " Replace this with whatever is needed to setup the correct dark mode for you
endfunction

function! LightMode()
  set background=light " Replace this with whatever is needed to setup the correct light mode for you
endfunction

if (filereadable(expand("~/.config/appearance/current")) && readfile(expand("~/.config/appearance/current"))[0] == "Light")
  call LightMode()
else
  call DarkMode()
endif