trufflesuite/truffle

function DeferredChain() {
  var self = this;
  this.chain = new Promise(function (accept, reject) {
    self._accept = accept;
    self._reject = reject;
  });

  this.await = new Promise(function () {
    self._done = arguments[0];
    self._error = arguments[1];
  });
  this.started = false;
}

DeferredChain.prototype.then = function (fn) {
  var self = this;
  this.chain = this.chain.then(function () {
    var args = Array.prototype.slice.call(arguments);

    return fn.apply(null, args);
  });
  this.chain = this.chain.catch(function (e) {
    self._error(e);
    throw e;
  });

  return this;
};

DeferredChain.prototype.catch = function (fn) {
  this.chain = this.chain.catch(function () {
    var args = Array.prototype.slice.call(arguments);

    return fn.apply(null, args);
  });

  return this;
};

DeferredChain.prototype.start = function () {
  this.started = true;
  this.chain = this.chain.then(this._done);
  this._accept();
  return this.await;
};

module.exports = DeferredChain;