Ignoring AJAX errors with promises array and $.when

Unfortunately, jQuery doesn't come with this functionality.

Gladly, you can implement it yourself pretty easily.

var url = 'http://gdata.youtube.com/feeds/api/videos/{{vid}}?v=2&alt=json';function getVideo(vid){    var u = url.replace('{{vid}}', vid);    return $.getJSON( u ).then(function(res){         return {video:vid,result:res.entry};    });}var promises = ['ozj2-bnTL3s','EAZ4Tlt8MQ4',"doesn'texist"].map(getVideo);some(promises).then(function(results){    for(var i = 0; i < results.length; i++) {        console.log(results[i]); // log    }});// get a hook on when all of the promises resolve, some fulfill// this is reusable, you can use this whenever you need to hook on some promises// fulfilling but all resolving.function some(promises){    var d = $.Deferred(), results = [];    var remaining = promises.length;    for(var i = 0; i < promises.length; i++){        promises[i].then(function(res){            results.push(res); // on success, add to results        }).always(function(res){            remaining--; // always mark as finished            if(!remaining) d.resolve(results);        })    }    return d.promise(); // return a promise on the remaining values}

Here's a working JSFiddle of the result.

In a purely javascript Promise implementation (or a specialised library like Q or another), you could do this:

function getVideo(id) {  return new Promise(function(resolve, reject) {    var request = new XMLHttpRequest();    request.open('GET', 'url = 'http://gdata.youtube.com/feeds/api/videos/' + id + '?v=2&alt=json');    request.onload = function() {      if (request.status == 200) {        resolve(request.response); //we get the data here. So, resolve the Promise      } else {        reject(Error(request.statusText)); //if status is not 200 OK, reject.      }    };    request.onerror = function() {      reject(Error("Error fetching data.")); //error occurred, reject the Promise    };    request.send(); //send the request  });}function fetchVideos() {  var vids = [    'ozj2-bnTL3s',    'EAZ4Tlt8MQ4',    'Xn9o7cxqVoA'    // ,'this-videoid-doesnot-exists'  ]  var promises = [];  for (var i in vids) {    promises.push(getVideo(vids[i]));  }  Promise.all(promises).then(function(dataArr) {    dataArr.forEach(function(data) {      console.log(data.entry);    });  }).catch(function(err){      console.log(err);  });}