How to use the kew.defer function in kew

var pkgPath = path.join(libPath, 'phantom')
var phantomPath = null
var tmpPath = null

// If the user manually installed PhantomJS, we want
// to use the existing version.
//
// Do not re-use a manually-installed PhantomJS with
// a different version.
//
// Do not re-use an npm-installed PhantomJS, because
// that can lead to weird circular dependencies between
// local versions and global versions.
// https://github.com/Obvious/phantomjs/issues/85
// https://github.com/Medium/phantomjs/pull/184
var whichDeferred = kew.defer()
which('phantomjs', whichDeferred.makeNodeResolver())
whichDeferred.promise
  .then(function (result) {
    phantomPath = result

    // Horrible hack to avoid problems during global install. We check to see if
    // the file `which` found is our own bin script.
    if (phantomPath.indexOf(path.join('npm', 'phantomjs')) !== -1) {
      console.log('Looks like an `npm install -g` on windows; unable to check for already installed version.')
      throw new Error('Global install')
    }

    var contents = fs.readFileSync(phantomPath, 'utf8')
    if (/NPM_INSTALL_MARKER/.test(contents)) {
      console.log('Looks like an `npm install -g`; unable to check for already installed version.')
      throw new Error('Global install')

function extractDownload(filePath) {
  var deferred = kew.defer()
  // extract to a unique directory in case multiple processes are
  // installing and extracting at once
  var extractedPath = filePath + '-extract-' + Date.now()
  var options = {cwd: extractedPath}

  mkdirp.sync(extractedPath, '0777')
  // Make double sure we have 0777 permissions; some operating systems
  // default umask does not allow write by default.
  fs.chmodSync(extractedPath, '0777')

  if (filePath.substr(-4) === '.zip') {
    console.log('Extracting zip contents')

    try {
      var zip = new AdmZip(filePath)
      zip.extractAllTo(extractedPath, true)

.fail(function (err) {
    // Trying to use a local file failed, so initiate download and install
    // steps instead.
    var npmconfDeferred = kew.defer()
    npmconf.load(npmconfDeferred.makeNodeResolver())
    return npmconfDeferred.promise
  })
  .then(function (conf) {

.fail(function (err) {
    // Trying to use a local file failed, so initiate download and install
    // steps instead.
    var npmconfDeferred = kew.defer()
    npmconf.load(npmconfDeferred.makeNodeResolver())
    return npmconfDeferred.promise
  })
  .then(function (conf) {

function destroy(pgtable, key) {
            var deferred = Q.defer();
            //show we first check if there is a record to delete - does this matter?

            pgclient.query("SELECT id FROM " + pgtable + " WHERE id='" + key + "'", function(err, result) {
                if (err) {
                    //console.error(pgtable, err);
                    deferred.reject(err);
                } else {
                    if (result.rows.length > 0) {
                        sql = "DELETE FROM " + pgtable + " WHERE id='" + key + "'";
                        pgclient.query(sql, function(err, result) {
                            if (err) {
                                console.err(pgtable + ": " + sql, err);
                                deferred.reject(err);
                            } else {
                                console.log(pgtable + ": " + key + " deleted");
                                deferred.resolve(result.rowCount);

function requestBinary(requestOptions, filePath) {
  var deferred = kew.defer()

  var writePath = filePath + '-download-' + Date.now()

  console.log('Receiving...')
  var bar = null
  requestProgress(request(requestOptions, function (error, response, body) {
    console.log('')
    if (!error && response.statusCode === 200) {
      fs.writeFileSync(writePath, body)
      console.log('Received ' + Math.floor(body.length / 1024) + 'K total.')
      fs.renameSync(writePath, filePath)
      deferred.resolve(filePath)

    } else if (response) {
      console.error('Error requesting archive.\n' +
          'Status: ' + response.statusCode + '\n' +

return function() {
            var p = q.defer();
            arguments[arguments.length++] = function(err, res) {
                if (err) p.reject(err);
                else p.resolve(res)
            };
            try {
                nodefn.apply(this, arguments);
            }
            catch (e) {
                p.reject(e);
            }
            return p;
        }
    }

UpnpInterface.prototype.getCurrentIP = function () {
	var self = this;

	var defer = libQ.defer();
	var ipaddr = '';

	ifconfig.status('wlan0', function(err, status) {
				if (status != undefined) {
						if (status.ipv4_address != undefined) {
							ipaddr = status.ipv4_address;
							defer.resolve(ipaddr);
							} else {
							ipaddr = ip.address();
							defer.resolve(ipaddr);
						}
					}
	});
	return defer.promise;
};

CoreStateMachine.prototype.pushState = function () {
	this.commandRouter.pushConsoleMessage('[' + Date.now() + '] ' + 'CoreStateMachine::pushState');

	var promise = libQ.defer();

	var state = this.getState();
	var self = this;
	self.commandRouter.volumioPushState(state)
		.then(function (data) {
			self.checkFavourites(state)
				.then(function (a) {
					promise.resolve({});
				})
		});

	return promise.promise;
};