git.js

// imports
var execFile = require('child_process').execFile;

// Class Git
var Git = module.exports = function (options) {
  this.binary = 'git';
  if (typeof options == 'undefined')
    options = {};

  this.cwd = options.cwd || process.cwd();
  delete options.cwd;

  this.args = Git.optionsToString(options);
};

// git.exec(command [[, options], args ], callback)
Git.prototype.exec = function (command, options, args, callback) {
  callback = arguments[arguments.length - 1];

  if (arguments.length == 2) {
    options = {};
    args = [];
  } else if (arguments.length == 3) {
    args = arguments[1];
    options = [];
  }

  options = Git.optionsToString(options)

  execFile(this.binary, [...this.args, command, ...options, ...args], {
    cwd: this.cwd
  }, function (err, stdout, stderr) {
    callback(err, stdout);
  });
};

// converts an object that contains key value pairs to a argv string
Git.optionsToString = function (options) {
  var args = [];

  for (var k in options) {
    var val = options[k];

    if (k.length == 1) {
      // val is true, add '-k'
      if (val === true)
        args.push('-'+k);
      // if val is not false, add '-k val'
      else if (val !== false)
        args.push('-'+k+' '+val);
    } else {
      if (val === true)
        args.push('--'+k);
      else if (val !== false)
        args.push('--'+k+'='+val);
    }
  }

  return args
};