node.js - Chaining promises -

node.js - Chaining promises -

what want accomplish parsing given website , writing title titles.txt. using request module fetching website , cheerio getting title.

i using q module creating next 2 promises:

readtitle

var readtitle = function(url) { var deferred = q.defer(); request({ url: url }, function(err, response, body) { var $ = cheerio.load(body); deferred.resolve($("title").text()); }); homecoming deferred.promise; };

writetitle

var writetitle = function(title) { var deferred = q.defer(); fs.appendfile('titles.txt', title + "\n", function() { deferred.resolve(); }); homecoming deferred.promise; };

i expect next script write google , stack overflow text file:

readtitle('http://www.google.com') .then(writetitle) .then(readtitle('http://www.stackoverflow.com')) .then(writetitle);

but is:

google undefined

what doing wrong?

then needs passed function rather value

.then(function() {return readtitle('http://www.stackoverflow.com'); }) .then(writetitle);

node.js promise q