function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

/*<replacement>*/

require('babel-polyfill');

var util = require('util');

for (var i in util) {

exports[i] = util[i];

} /*</replacement>*/ /*<replacement>*/

if (!global.setImmediate) {

global.setImmediate = function setImmediate(fn) {

return setTimeout(fn.bind.apply(fn, arguments), 4);

};

}

if (!global.clearImmediate) {

global.clearImmediate = function clearImmediate(i) {

return clearTimeout(i);

};

}

/*</replacement>*/

/* eslint-disable required-modules */

'use strict';

/*<replacement>*/

var objectKeys = objectKeys || function (obj) {

var keys = [];

for (var key in obj) {

keys.push(key);

}return keys;

};

/*</replacement>*/

var _require = require('stream'),

Duplex = _require.Duplex;

var assert = require('assert');

var kCallback = Symbol('Callback');

var kOtherSide = Symbol('Other');

var DuplexSocket = function (_Duplex) {

_inherits(DuplexSocket, _Duplex);

function DuplexSocket() {

_classCallCheck(this, DuplexSocket);

var _this = _possibleConstructorReturn(this, _Duplex.call(this));

_this[kCallback] = null;

_this[kOtherSide] = null;

return _this;

}

DuplexSocket.prototype._read = function _read() {

var callback = this[kCallback];

if (callback) {

this[kCallback] = null;

callback();

}

};

DuplexSocket.prototype._write = function _write(chunk, encoding, callback) {

assert.notStrictEqual(this[kOtherSide], null);

assert.strictEqual(this[kOtherSide][kCallback], null);

this[kOtherSide][kCallback] = callback;

this[kOtherSide].push(chunk);

};

DuplexSocket.prototype._final = function _final(callback) {

this[kOtherSide].on('end', callback);

this[kOtherSide].push(null);

};

return DuplexSocket;

}(Duplex);

function makeDuplexPair() {

var clientSide = new DuplexSocket();

var serverSide = new DuplexSocket();

clientSide[kOtherSide] = serverSide;

serverSide[kOtherSide] = clientSide;

return { clientSide: clientSide, serverSide: serverSide };

}

module.exports = makeDuplexPair;

function forEach(xs, f) {

for (var i = 0, l = xs.length; i < l; i++) {

f(xs[i], i);

}

}