ref: 4907b8d3554aae7f7f2c298a73f7f512f0ead2ed firenvim/README.md -rw-r--r-- 13.8 KiB
4907b8d3glacambre Improve testsuite 2 years ago

#Firenvim Build Status Build status Total alerts Vint

Turn your browser¹ into a Neovim client.

¹ Firefox and Chrome are specifically supported. Other Chromium based browsers such as Brave, Vivaldi, and Opera should also work but are not specifically tested.

Firenvim demo

#How to use

Just click on any textarea and it will be immediately replaced by an instance of Firenvim. When you want to set the content of the now hidden textarea to the content of the Neovim instance, just :w. If you want to close the Firenvim overlay and return to the textarea run :q. If you selected an element where you expected the Firenvim frame to appear and it didn't, try pressing <C-e>.


Before installing anything please read SECURITY.md and make sure you're okay with everything mentioned. In the event you think of a way to compromise Firenvim, please send me an email (you can find my address in my commits).


  1. Make sure you are using Neovim 0.4.0 or later. This plugin will not work with vanilla VIM or Vimr.

  2. Check if the luabitop package is available by running :lua bit.band(1,1) in Neovim. If this throws an error, you will need to install it.

  3. Install Firenvim as a VIM plugin as you would any other, then run the built in post-install hook script.

    • vim-plug

      Plug 'glacambre/firenvim', { 'do': { _ -> firenvim#install(0) } }
    • dein

      call dein#add('glacambre/firenvim', { 'hook_post_update': { _ -> firenvim#install(0) } })
    • minpac

      call minpac#add('glacambre/firenvim', { 'type': 'opt', 'do': 'packadd firenvim | call firenvim#install(0)'})

      To load Firenvim when needed:

      if exists('g:started_by_firenvim')
        packadd firenvim
    • pathogen, vundle, others

      Install the plugin as you usually would, then run this shell command:

      $ nvim --headless "+call firenvim#install(0) | q"
  4. Finally install Firenvim in your browser from Mozilla's store or Google's.

#From source


Installing from source requires NodeJS, npm, and Neovim >= 0.4.

#Cross-browser steps

First, install Firenvim like a regular vim plugin (either by changing your runtime path manually or by using your favourite plugin manager).

Then, run the following commands:

git clone https://git.sr.ht/~glacambre/firenvim
cd firenvim
npm install
npm run build
npm run install_manifests

These commands should create three directories: target/chrome, target/firefox and target/xpi.

#Firefox-specific steps

Go to about:addons, click on the cog icon and select install addon from file (note: this might require setting xpinstall.signatures.required to false in about:config).

#Google Chrome/Chromium-specific steps

Go to chrome://extensions, enable "Developer mode", click on Load unpacked and select the target/chrome directory.

#Other browsers

Other browsers aren't supported for now. Opera, Vivaldi and other Chromium-based browsers should however work just like in Chromium and have similar install steps. Brave and Edge might work, Safari doesn't (it doesn't support Webextensions).


Firenvim currently requires the following permissions for the following reasons:

#Configuring Firenvim

#Manually triggering Firenvim

You can configure the keybinding to manually trigger Firenvim (<C-e> by default) in the shortcuts menu in about://addons on Firefox, or in chrome://extensions/shortcuts on Chrome.

#Temporarily disabling Firenvim in a tab

Temporarily disabling (and re-enabling) Firenvim in a tab can be done either by clicking on the Firenvim button next to the urlbar or by configuring a browser shortcut (see the previous section to find out how browser shortcuts can be configured).

#Building a Firenvim-specific config

When it starts Neovim, Firenvim sets the variable g:started_by_firenvim which you can check to run different code in your init.vim. For example:

if exists('g:started_by_firenvim')
  set laststatus=0
  set laststatus=2

Alternatively, you can detect when Firenvim connects to Neovim by using the UIEnter autocmd event:

function! s:IsFirenvimActive(event) abort
  if !exists('*nvim_get_chan_info')
    return 0
  let l:ui = nvim_get_chan_info(a:event.chan)
  return has_key(l:ui, 'client') && has_key(l:ui.client, "name") &&
      \ l:ui.client.name is# "Firenvim"

function! OnUIEnter(event) abort
  if s:IsFirenvimActive(a:event)
    set laststatus=0
autocmd UIEnter * call OnUIEnter(deepcopy(v:event))

Similarly, you can detect when Firenvim disconnects from a Neovim instance with the UILeave autocommand.

#Using different settings depending on the page/element being edited

If you want to use different settings depending on the textarea you're currently editing, you can use autocommands to do that too. All buffers are named like this: domainname_page_selector.txt (see the toFileName function). This means that you can for example set the file type to markdown for all GitHub buffers:

au BufEnter github.com_*.txt set filetype=markdown

#Understanding Firenvim's configuration object

You can configure the rest of Firenvim by creating a variable named g:firenvim_config in your init.vim. This variable is a dictionary containing the keys "globalSettings" and "localSettings". g:firenvim_config["localSettings"] is a dictionary the keys of which have to be a Javascript pattern matching a URL and the values of which are dictionaries containing settings that apply for all URLs matched by the Javascript pattern. When multiple patterns match a same URL, the pattern with the highest "priority" value is used. Here is an example (the settings and their possible values will be explained in the next subsections):

let g:firenvim_config = { 
    \ 'globalSettings': {
        \ 'alt': 'all',
    \  },
    \ 'localSettings': {
        \ '.*': {
            \ 'cmdline': 'neovim',
            \ 'priority': 0,
            \ 'selector': 'textarea',
            \ 'takeover': 'always',
        \ },
    \ }
\ }

With this configuration, takeover will be set to always on all websites. If we wanted to override this value on british websites, we could add the following lines to our init.vim. Notice how the priority of this new regex is higher than that of the .* regex:

let fc = g:firenvim_config['localSettings']
let fc['https?://[^/]+\.co\.uk/'] = { 'takeover': 'never', 'priority': 1 }

From now on, localSettings examples will use the let fc[...] = ... shorthand, assuming that you have a line like let fc = g:firenvim_config['localSettings'] in your config.

#Configuring what elements Firenvim should appear on

The selector attribute of a localSetting controls what elements Firenvim automatically takes over. Here's the default value:

let fc['.*'] = { 'selector': 'textarea, div[role="textbox"]' }

If you don't want to use Firenvim with rich text editors (e.g. Gmail, Outlook, Slack…) as a general rule, you might want to restrict Firenvim to simple textareas:

let fc['.*'] = { 'selector': 'textarea' }

#Configuring Firenvim to not always take over elements

Firenvim has a setting named takeover that can be set to always, empty, never, nonempty or once. When set to always, Firenvim will always take over elements for you. When set to empty, Firenvim will only take over empty elements. When set to never, Firenvim will never automatically appear, thus forcing you to use a keyboard shortcut in order to make the Firenvim frame appear. When set to nonempty, Firenvim will only take over elements that aren't empty. When set to once, Firenvim will take over elements the first time you select them, which means that after :q'ing Firenvim, you'll have to use the keyboard shortcut to make it appear again. Here's how to use the takeover setting:

let fc['.*'] = { 'takeover': 'always' }

#Using the external command line

You can chose to use an external command line (and thus save a line of space) by setting the localSetting named cmdline to firenvim. It's default value is neovim:

let fc['.*'] = { 'cmdline' : 'firenvim' }

#Special characters on OSX

On OSX, on certain layouts (e.g. the swedish layout), pressing special characters (e.g. @) requires combining Alt and another key. Because of browser/OS limitations, it is impossible to tell the difference between a user trying to press <A-@> and just @. Because of that, on OSX, Firenvim decides to ignore the Alt key when you press any non-alphanumerical key. This behavior can be changed by setting the alt setting of the globalSettings configuration to all, like this:

let g:firenvim_config = {
	\ "globalSettings": {
		\ "alt": "all"

Non-OSX users can get the default OSX behavior by setting the alt setting to alphanum (but they shouldn't ever need to do that).

#Interacting with the page

You can move focus from the editor back to the page or the input field by calling firenvim#focus_page or firenvim#focus_input. Here's an example that does exactly this if you press <Esc> twice while in normal mode:

nnoremap <Esc><Esc> :call firenvim#focus_page()<CR>

There is also a function named firenvim#hide_frame() which will temporarily hide the Firenvim frame. You will then be able to bring the neovim frame back either by unfocusing and refocusing the textarea or by using the keybinding to manually trigger Firenvim.

nnoremap <C-z> :call firenvim#hide_frame()<CR>

A function named firenvim#press_keys() will allow you to send key events to the underlying input field by taking a list of vim-like keys (e.g. a, <CR>, <Space>…) as argument. Note that this only "triggers" an event, it does not add text to the input field. It can be useful with chat apps, if used like this:

au BufEnter riot.im_* inoremap <CR> <Esc>:w<CR>:call firenvim#press_keys("<LT>CR>")<CR>ggdGa

Known Issues: some chat apps do not react to firenvim#press_keys (e.g. Slack). Others steal focus from the neovim frame (e.g. Riot.im).

#Automatically syncing changes to the page

Since Firenvim just uses the BufWrite event in order to detect when it needs to write neovim's buffers to the page, Firenvim can be made to automatically synchronize all changes like this:

au TextChanged * ++nested write
au TextChangedI * ++nested write

Depending on how large the edited buffer is, this could be a little slow. A better approach would then be to delay writes, like this:

let g:dont_write = v:false
function! My_Write(timer) abort
	let g:dont_write = v:false

function! Delay_My_Write() abort
	if g:dont_write
	let g:dont_write = v:true
	call timer_start(10000, 'My_Write')

au TextChanged * ++nested call Delay_My_Write()
au TextChangedI * ++nested call Delay_My_Write()


The main issue with Firenvim is that some keybindings (e.g. <C-w>) are not overridable. I circumvent this issue by running a patched version of Firefox.

#You might also like

  • Tridactyl, provides vim-like keybindings to use Firefox. Also lets you edit input fields and text areas in your favourite editor with its :editor command.
  • GhostText, lets you edit text areas in your editor with a single click. Requires installing a plugin in your editor too. Features live updates!
  • Textern, a Firefox addon that lets you edit text areas in your editor without requiring you to install a plugin in your editor.
  • withExEditor, same thing as Textern, except you can also edit/view a page's source with your editor.