javascript - Promise middleware in node js callback functions how to use multiple then? -

am newby in node js, using promise middleware in node js. didn't find documentation useful me , unable understand how use 2 callbacks in 1 request or how should use multiple then. please me thanks.

here code

//get application types var p1 = new promise(function(resolve, reject) {   console.log("in p1");   var url = turl+'applicationtype/getall'   var args = {     headers:{"authkey": req.session.name}   };   client.get(url, args, function(data,response) {       console.log(data, "in app type req");       if(data.status == "success"){         return resolve(data);       }       else{         reject ("unamble data!")       }   }); });  p1.then(function(data) {   console.log(data.response.applicationtype, "in p1 then", data)   //load page after data   res.render('app', {     message: req.session.name,     uname: "the mechanic",     applist: data.response.applicationtype   }); },function(reason) {   console.log(reason, "reason in not then"); // error! });    //get application var p2 = new promise(function(resolve, reject){   console.log("in p2");   var url = turl+'applications'   var args = {     headers:{"authkey": req.session.name}   };   client.get(url, args, function(data,response) {       console.log(data, "in app req");       if(data.status == "success"){         return resolve(data);       }       else{         reject ("unamble data!")       }   }); });  p2.then(function(data) {   console.log(data.response, "in p2 then", data)   //load page after data   res.render('app', {     applist: data.response   });  },function(reason) {   console.log(reason, "reason in not p2"); // error! }); 

solutions looking for 1. have send data on page after both request complete. 2. how can manage response in object , send page using render or alternative?

my first advice find way promisify client.get in native fashion, not sure lib represent, , not following node-style callback fun(err, data), aside, assuming, have single request server, carry multiple requests else, bundle responses , respond requester right?

i restructure code like

function pget(url, args){   return new promise(function(resolve, reject){     client.get(url, args, function(data, response){       if(data.status === 'success') resolve(data);       else reject('unable data');     });   }); }  router.get('/api/someapi', function(req, res, next){   var resultjson = {     message: req.session.name,     uname: "the mechanic"   }, args = { headers:{"authkey": req.session.name} },   p1, p2;    p1 = pget(turl+'applicationtype/getall', args)     .then(function(data){       resultjson.applist = data.response.applicationtype;     }).catch(console.log.bind(console));    p2 = pget(turl+'applications', args)     .then(function(data){       resultjson.applist = data.response;     }).catch(console.log.bind(console));    // send response once both of promises finish   promise.all([p1, p2]).then(function(){     res.render('app', resultjson);    }); // not adding error handler since both previous ones should not throw any.  });