Open files in existing neovim instance in iTerm

script.js

/*

Requirements:
* iTerm
* nvim
* nvr

Install:
1. New application in Automator
2. Add Run JavaScript action
3. Add below
4. Save
5. Open files with application

*/

var iTerm = Application('iTerm');
if(!iTerm.running()) iTerm.launch();
  
var app = Application.currentApplication();
app.includeStandardAdditions = true;

function run(input) {
  if (input.length == 0 || input.length == undefined) return;
  
  openIn(input, app.doShellScript("/usr/local/bin/nvr --serverlist | uniq").split('\r').map(function getCwd(sock) {
    return {
      socket: sock,
      cwd: app.doShellScript("/usr/local/bin/nvr --remote-expr 'getcwd()' --servername " + sock),
    };
  }).reduce(function checkForUniqueness(memo, instance) {
  	if (memo.paths[instance.cwd]) {
	  memo.paths[instance.cwd] += 1;
	} else {
	  memo.paths[instance.cwd] = 1;
    }
    memo.sockets[instance.cwd + (memo.paths[instance.cwd] == 1 ? '' : ' (' + memo.paths[instance.cwd] + ')')] = instance.socket;
	return memo;
  }, {sockets: {}, paths: {}}).sockets);
}

function openIn(files, sockets) {
  var fileNames = "'" + files.join("' '") + "'";
  var newInstance = 'A new instance';
  var options = Object.keys(sockets);
  options.push(newInstance);
  if (options.length == 1) return iTerm.write(iTerm.createTabWithDefaultProfile(iTerm.windows.first).currentSession, {text: 'nvim ' + fileNames});
  
  var answer = app.chooseFromList(options, {
    defaultItems: [newInstance],
    withTitle: 'Open in nvim',
	withPrompt: 'Please select which instance of nvim you’d like to open the file' + (files.length > 1 ? 's' : '') + ' in:',
	multipleSelectionsAllowed: false,
	emptySelectionAllowed: false,
  })[0];
  
  switch (answer) {
    case undefined:
	  return;
    case 'A new instance':
      return openIn(files, {});
	default:
	  return app.doShellScript('/usr/local/bin/nvr --servername ' + sockets[answer] + ' --remote-tab ' + fileNames);
  }
}