fix(browser support): do not use process.nextTick without check that …

…it exists (#1136)

lib/client.js

@@ -12,9 +12,10 @@ var reInterval = require('reinterval')
 var validations = require('./validations')
 var xtend = require('xtend')
 var debug = require('debug')('mqttjs:client')
+var nextTick = process ? process.nextTick : function (callback) { setTimeout(callback, 0) }
 var setImmediate = global.setImmediate || function (callback) {
  // works in node v0.8
- process.nextTick(callback)
+ nextTick(callback)
 }
 var defaultConnectOptions = {
  keepalive: 60,
@@ -303,7 +304,7 @@ MqttClient.prototype._setupStream = function () {
 
  function nextTickWork () {
  if (packets.length) {
- process.nextTick(work)
+ nextTick(work)
  } else {
  var done = completeParse
  completeParse = null
@@ -838,8 +839,8 @@ MqttClient.prototype.end = function (force, opts, cb) {
  debug('end :: (%s) :: finish :: calling _cleanUp with force %s', that.options.clientId, force)
  that._cleanUp(force, () => {
  debug('end :: finish :: calling process.nextTick on closeStores')
- // var boundProcess = process.nextTick.bind(null, closeStores)
- process.nextTick(closeStores.bind(that))
+ // var boundProcess = nextTick.bind(null, closeStores)
+ nextTick(closeStores.bind(that))
  }, opts)
  }
 

lib/connect/wx.js

@@ -117,13 +117,13 @@ function buildStream (client, opts) {
  stream.destroy = destroyRef
 
  var self = this
- process.nextTick(function () {
+ setTimeout(function () {
  socketTask.close({
  fail: function () {
  self._destroy(new Error())
  }
  })
- })
+ }, 0)
  }.bind(stream)
 
  bindEventHandler()

lib/store.js

@@ -88,9 +88,9 @@ Store.prototype.createStream = function () {
 
  destroyed = true
 
- process.nextTick(function () {
+ setTimeout(function () {
  self.emit('close')
- })
+ }, 0)
  }
 
  return stream