Send mocha error msg back to macvim quickfix

error-parser.js

#!/usr/bin/env node
// Warning: clientserver feature required for MacVim, check it by `:echo has('clientserver')` in MacVim
'use strict'
var lstream = require('./lstream')
var stream = new lstream()
var exec = require('child_process').exec

var hasError = false
stream.on('line', function (line) {
  if (line.length) {
    var s = line.replace(/^[\s]+/, '')
    if (/^at/.test(s)) {
      var ms = s.match(/^(.*)\s\((.*):(\d+):(\d+)\)/)
      if (!ms) {
        ms = s.match(/^(.*)\s([^\s]+):(\d+):(\d+)/)
      }
      var str = ms[2] + ':' + ms[3] + ':' + ms[4] + ' ' + ms[1]
      sendMsg(":caddexpr '" + str + "'")
      hasError = true
    }
  }
  return line
})

stream.on('finish', function () {
  var code = hasError ? 1 : 0
  if (hasError) {
    process.exit(1)
  } else {
    sendMsg('ccl')
  }
})

function sendMsg(cmd) {
  exec('mvim --remote-send "' + cmd + '<cr>"', function (err, stdout, stderr) {
    if (err !== null) console.log(err)
    if (stderr) console.log(stderr)
  })
}

sendMsg(':set errorformat=%f:%l:%c\\ %m')
sendMsg(':cex []')

process.stdin.pipe(stream).pipe(process.stdout)

lstream.js

var stream = require('stream');
var util = require('util');

var LineStream = module.exports = function LineStream(opts) {
  if (!(this instanceof LineStream)) return new LineStream(opts);
  opts = opts || {};
  opts.objectMode = true;
  stream.Transform.call(this, opts);
  this._buff = '';
};
util.inherits(LineStream, stream.Transform);


LineStream.prototype._transform = function(chunk, encoding, done) {
  var data = this._buff + chunk.toString('utf8');
  var lines = data.split(/\r?\n|\r(?!\n)/);

  this._buff = lines.pop();

  var self = this;

  lines.forEach(function (line) {
    self._line(line + '\n');
  });

  done();
};


LineStream.prototype._flush = function(done) {
  if (this._buff) this._line(this._buff);
  done();
};


LineStream.prototype._line = function(line) {
  this.push(line);
  this.emit('line', line);
};