javascript - Change async workflow to Promise (Bluebird) -

i have been trying wrap head around promises. basic concepts understand, once gets nested, little bit confused. feedback appreciated

here code trying refactor promises (bluebird)

var getindividualdata = function(url, donegetindividualdata) {     var $, data;      request(url, function(err, res, body) {         if (!err && res.statuscode === 200) {             $ = cheerio.load(body);              data = {                 title: $("#itemtitle").children()["0"].next.data,                 condition: $("#vi-itm-cond").text(),                 price: $("#prcisum_bidprice").text(),                 imgurl: $("#icimg")[0].attribs.src,                 createdat: chance.date(),                 likes: chance.integer({min: 0, max: 1000})             };              donegetindividualdata(null, data);         } else {             donegetindividualdata(err);         }     }); };  var getlisting = function(url, donegetlisting) {     var $;     var links = [];      request(url, function(err, res, body) {         if (!err && res.statuscode === 200) {             $ = cheerio.load(body);              $('.vip').each(function(i, el) {                 if (i < 15) {                     links.push(el.attribs.href);                 }             });              async                 .concat(links, getindividualdata, function(err, result) {                     return donegetlisting(null, result);                 });         } else {             donegetlisting(err);         }     }); };  var puttomongo = function(err, result) {     if (devconfig.seeddb) {         mongoose.connect(devconfig.mongo.uri);          item.find({}).remove(function(err, items) {             item.create(result, function(err, items) {                 console.log('done');                 process.kill();             });         });     } };  async     .concat(urls, getlisting, puttomongo); 

the first thing wrap request in returns promise. many promise libraries have utilities "promisifying" async functions, don't think that'll work here because request passes 2 success values callback:

var requestasync = function(url) {     return new promise(function (resolve, reject) {         request(function (err, res, body) {             if (err) {                 reject(err);             }             resolve({ res: res, body: body});         });    }); }; 

once that's done, gets lot easier:

var getindividualdata = function(url) {     return requestasync(url).then(function (result) {         if (result.res.statuscode === 200) {             var $ = cheerio.load(result.body);              return {                 title: $("#itemtitle").children()["0"].next.data,                 condition: $("#vi-itm-cond").text(),                 price: $("#prcisum_bidprice").text(),                 imgurl: $("#icimg")[0].attribs.src,                 createdat: chance.date(),                 likes: chance.integer({min: 0, max: 1000})             };         }          throw new error("individual data status code: " + result.res.statuscode);     }); };  var getlisting = function(url, donegetlisting) {     return requestasync(url).then(function (result) {         if (result.res.statuscode === 200) {             var $ = cheerio.load(result.body),                 promises = $('.vip').filter(function (i) {                      return < 15;                 }).map(function (i, el) {                     return getindividualdata(el.attribs.href);                 });              return promise.all(promises);         }          throw new error("listing status code: " + result.res.statuscode);     }); };  var puttomongo = function(result) {     if (devconfig.seeddb) {         mongoose.connect(devconfig.mongo.uri);          item.find({}).remove(function(err, items) {             item.create(result, function(err, items) {                 console.log('done');                 process.kill();             });         });     } };  promise.all(urls.map(getlisting)) .then(puttomongo) .catch(function (err) {     // handle error });