javascript - nodeschool exercise solving with promises -

i solving nodeschool exercise "juggling async" , solved this

var http=require("http"); var urls=process.argv.slice(2,process.argv.length); var count=0; var junge=[]; urls.map(function(url,index){ http.get(url,function(response){     var str="";     response.setencoding("utf-8");      response.on("data",function(data){str=str+data})     response.on("end",function(){         junge.push(str);         count++;         if(index==urls.length-1) junge.map(function(v){console.log(v)})      });  });}) 

(it works) thinking how exercise looked if used promises? tried this

var http=require("http"); var urls=process.argv.slice(2,process.argv.length); var count=0; var fin=[]; var promise=function(x){     return new promise(function(resolve,reject){         http.get(x,function(response){             response.setencoding("utf-8");             var junge=[];             response.on("data",function(data){                 junge.push(data);             });             response.on("end",function(){                 resolve(junge)             })         })      }         )     }     function printitfgt(x){         var m=promise(x);         return m.then(function(response){             fin.pus(response)                     })     } urls.foreach(function(x,index){     printitfgt(x);     if(index==urls.length-1) console.log(fin) }) 

but code not pass expectation , says failed. in case assume code not work or has bug in fail see. sulution promises then?

erazihel right, you're missing reject. how wrap promises, put little code inside promise constructor executor function possible, e.g. minimal drop-in fills absence of function supports promises.

also, see no reason not use promise.all urls in parallel (faster):

promise.all(urls.map(function(url) {   return new promise(function(resolve, reject) {     var str = "";     http.get(url, function(response) {       response.on("data", function(data) { str+=data; });       response.on("end", function() { resolve(str); });       response.error("end", function() { reject(str); });     });   }); })) .then(function(junge) {   console.log(junge); }) .catch(function(e) { console.log(e); }); 

i @ using fetch, if available.

var console = { log: function(msg) { div.innerhtml += msg + "<br>"; }};  var http = { get: function(u, f) {    f({ on: function(name, f) { f(name == "data" && u); }});  }};  var urls=["result1", "result2"];    promise.all(urls.map(function(url,index) {    return new promise(function(resolve, reject) {      var str = "";      http.get(url, function(response) {        response.on("data", function(data) { str+=data; });        response.on("end", function() { resolve(str); });        response.error("end", function() { reject(str); });      });    });  }))  .then(function(junge) {    console.log(junge);  })  .catch(function(e) { console.log(e); });

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