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Remove the map function

I have the following javascript promise, I'm looping through a list of documents, upload them one by one to Dropbox (API call), get back a shared link for each one of the documents, save them in an array and then generate an email with these links.
docs = self.checkedDocs();
body = "Please click on the link(s) below to view your document(s): ";
$.when.apply($, docs.map(function (doc) {
return self.service.getDropboxLink(doc).then(function (dropboxLink) {
return lineBreak + doc.documentDescription() + ": " + dropboxLink;
});
})).done(function () {
var attachment = [].join.call(arguments, '');
formatEmail(attachment, body);
});
What I'm trying to do is the exact same thing but for only one document, I understand that I don't need the map anymore but I'm not sure how to do it.
Could you help?

The $.when construct is used precisely because you want to wait for several promises. With only one document, most of the complexity goes away:
self.service.getDropboxLink(doc).then(function(dropboxLink) {
var attachment = doc.documentDescription() + ": " + dropboxLink;
openEmail("Please click on the link below to view your document: ", attachment);
});

Twitch TV JSON API Issue

So,I am trying to use the twitch API:
https://codepen.io/sterg/pen/yJmzrN
If you check my codepen page you'll see that each time I refresh the page the status order changes and I can't figure out why is this happening.
Here is my javascript:
$(document).ready(function(){
var ur="";
var tw=["freecodecamp","nightblue3","imaqtpie","bunnyfufuu","mushisgosu","tsm_dyrus","esl_sc2"];
var j=0;
for(var i=0;i<tw.length;i++){
ur="https://api.twitch.tv/kraken/streams/"+tw[i];
$.getJSON(ur,function(json) {
$(".tst").append(JSON.stringify(json));
$(".name").append("<li> "+tw[j]+"<p>"+""+"</p></li>");
if(json.stream==null){
$(".stat").append("<li>"+"Offline"+"</li>");
}
else{
$(".stat").append("<li>"+json.stream.game+"</li>");
}
j++;
})
}
});

$.getJSON() works asynchronously. The JSON won't be returned until the results come back. The API can return in different orders than the requests were made, so you have to handle this.
One way to do this is use the promise API, along with $.when() to bundle up all requests as one big promise, which will succeed or fail as one whole block. This also ensures that the response data is returned to your code in the expected order.
Try this:
var channelIds = ['freecodecamp', 'nightblue3', 'imaqtpie', 'bunnyfufuu', 'mushisgosu', 'tsm_dyrus', 'esl_sc2'];
$(function () {
$.when.apply(
$,
$.map(channelIds, function (channelId) {
return $.getJSON(
'https://api.twitch.tv/kraken/streams/' + encodeURIComponent(channelId)
).then(function (res) {
return {
channelId: channelId,
stream: res.stream
}
});
})
).then(function () {
console.log(arguments);
var $playersBody = $('table.players tbody');
$.each(arguments, function (index, data) {
$playersBody.append(
$('<tr>').append([
$('<td>'),
$('<td>').append(
$('<a>')
.text(data.channelId)
.attr('href', 'https://www.twitch.tv/' + encodeURIComponent(data.channelId))
),
$('<td>').text(data.stream ? data.stream.game : 'Offline')
])
)
})
})
});
https://codepen.io/anon/pen/KrOxwo
Here, I'm using $.when.apply() to use $.when with an array, rather than list of parameters. Next, I'm using $.map() to convert the array of channel IDs into an array of promises for each ID. After that, I have a simple helper function with handles the normal response (res), pulls out the relevant stream data, while attaching the channelId for use later on. (Without this, we would have to go back to the original array to get the ID. You can do this, but in my opinion, that isn't the best practice. I'd much prefer to keep the data with the response so that later refactoring is less likely to break something. This is a matter of preference.)
Next, I have a .then() handler which takes all of the data and loops through them. This data is returned as arguments to the function, so I simply use $.each() to iterate over each argument rather than having to name them out.
I made some changes in how I'm handling the HTML as well. You'll note that I'm using $.text() and $.attr() to set the dynamic values. This ensures that your HTML is valid (as you're not really using HTML for the dynamic bit at all). Otherwise, someone might have the username of <script src="somethingEvil.js"></script> and it'd run on your page. This avoids that problem entirely.

It looks like you're appending the "Display Name" in the same order every time you refresh, by using the j counter variable.
However, you're appending the "Status" as each request returns. Since these HTTP requests are asynchronous, the order in which they are appended to the document will vary each time you reload the page.
If you want the statuses to remain in the same order (matching the order of the Display Names), you'll need to store the response data from each API call as they return, and order it yourself before appending it to the body.

At first, I changed the last else condition (the one that prints out the streamed game) as $(".stat").append("<li>"+jtw[j]+": "+json.stream.game+"</li>"); - it was identical in meaning to what you tried to achieve, yet produced the same error.
There's a discrepancy in the list you've created and the data you receive. They are not directly associated.
It is a preferred way to use $(".stat").append("<li>"+json.stream._links.self+": "+json.stream.game+"</li>");, you may even get the name of the user with regex or substr in the worst case.
As long as you don't run separate loops for uploading the columns "DisplayName" and "Status", you might even be able to separate them, in case you do not desire to write them into the same line, as my example does.
Whatever way you're choosing, in the end, the problem is that the "Status" column's order of uploading is not identical to the one you're doing in "Status Name".

This code will not preserve the order, but will preserve which array entry is being processed
$(document).ready(function() {
var ur = "";
var tw = ["freecodecamp", "nightblue3", "imaqtpie", "bunnyfufuu", "mushisgosu", "tsm_dyrus", "esl_sc2"];
for (var i = 0; i < tw.length; i++) {
ur = "https://api.twitch.tv/kraken/streams/" + tw[i];
(function(j) {
$.getJSON(ur, function(json) {
$(".tst").append(JSON.stringify(json));
$(".name").append("<li> " + tw[j] + "<p>" + "" + "</p></li>");
if (json.stream == null) {
$(".stat").append("<li>" + "Offline" + "</li>");
} else {
$(".stat").append("<li>" + json.stream.game + "</li>");
}
})
}(i));
}
});
This code will preserve the order fully - the layout needs tweaking though
$(document).ready(function() {
var ur = "";
var tw = ["freecodecamp", "nightblue3", "imaqtpie", "bunnyfufuu", "mushisgosu", "tsm_dyrus", "esl_sc2"];
for (var i = 0; i < tw.length; i++) {
ur = "https://api.twitch.tv/kraken/streams/" + tw[i];
(function(j) {
var name = $(".name").append("<li> " + tw[j] + "<p>" + "" + "</p></li>");
var stat = $(".stat").append("<li></li>")[0].lastElementChild;
console.log(stat);
$.getJSON(ur, function(json) {
$(".tst").append(JSON.stringify(json));
if (json.stream == null) {
$(stat).text("Offline");
} else {
$(stat).text(json.stream.game);
}
}).then(function(e) {
console.log(e);
}, function(e) {
console.error(e);
});
}(i));
}
});

How to slow down an Ajax call?

I have a function in JS contains a loop, that calls an AJAX call every iteration. The call to inserts checked elements into a DB and returns the results of those elements in the same page in the next section.
The problem I have is that when I check for e.g. 4 checkboxes out of 3 groupes, the only checkboxes of the last group gets added to the page. However, when I use alert(), I can see all elements.
I used setTimeout, but I got error in the code. I also added lines to give more time to AJX call, but the problem remains. So I wonder if there is a solution to slow down the code without using alert().
This is my script:
addAptitudeField : function(currentAutocompleteField, idChamp) {
var currentAutocompleteFieldBind = currentAutocompleteField;
var idChampBind = idChamp;
window.setTimeout(function() {
// Code ...
var paramDwr = {};
var newDivName = "div" + idChamp + lastValueId;
paramDwr[attributs.r_divId] = newDivName;
paramDwr[attributs.r_currentValue] = currentValue;
paramDwr[attributs.r_hiddenIdsField] = hiddenIdsField.id;
paramDwr[attributs.r_lastValueId] = lastValueId;
paramDwr[attributs.r_itemmod] = nbAptitudesCat % 2 == 0;
// setTimeout ( RepertoireDwr.ligneSuppEtSpanMessage, 1000 ) doesn't work
RepertoireDwr.ligneSuppEtSpanMessage(paramDwr, function(ajaxPage) {
divCategorie.update(divCategorie.innerHTML + ajaxPage.texte);
aptitudeAvecDetail.remetsValeursStockees();
var btnSuppression = $(newDivName).getElementsByTagName('img')[0];
btnSuppression.setAttribute("onclick", "formulaireFiche.updateCSS('" + newDivName + "');" + btnSuppression.getAttribute("onclick") + "fiche.updateCategorieSuppressionAptLieeUo(\'divCat" + currentCategorie + "\');"); });
}
//
// alert() : It works in this case.
//
// for (var i=0; i<5000000; i++) ; it doesn't work
}, 400);
}
Thank you in advance for your help and time.

I will likely be downvoted for mentioning this, because it is not a recommended procedure, but I believe every coder should have all facts.
In jQuery AJAX construct, there is option async:false, which will delay the script from continuing UNTIL the AJAX has completed processing. Needless to say, if things go wrong in the AJAX the browser could freeze. A lot depends on who your users are, and amount of traffic -- on a few of my ten-user in-house projects it was an acceptable solution.
$.ajax({
async: false,
type: 'post',
url: 'ajax/ax.php',
data: 'request=',
success: function(d){
if (d.length) alert(d);
}
});
Ref:
What does "async: false" do in jQuery.ajax()?
The better idea, however, is to look into the Promises interface, with methods like .when() and .then()
References:
https://jsfiddle.net/v86bc028/2/
http://jqfundamentals.com/chapter/ajax-deferreds#
http://digitizor.com/jquery-html-callback-function-using-promise/#
how does jquery's promise method really work?

The problem you're running into deals with asynchronous functions, or the A in AJAX. If you don't know what an asynchronous function is, there are many others who can explain it better than I can, so give that a google.
What's happening without the alert() in there is your code makes 4 sever calls, but all 4 get sent out before you get a response to any of them. With the alert() (or setTimeout), you're giving the code time to received each response to a call before the next one is made.
There are several ways you can approach this, the first way is by calling the next call after the first receives a response. The second way is to use an async function to call all 4 at once on different chains(?). I'm not the best at explaining this part, but there's plenty of code to be found on SO and online.

I think you have a more generic problem in your code, since you seem to need to delay your executions to wait till sth. else is finished, instead of getting anounced when it is done.
The line that annoys me most is this one
divCategorie.update(divCategorie.innerHTML + ajaxPage.texte);
what exactly is update doing? How is it implemented?
I assume it does sth. like divCategorie.innerHTML += ajaxPage.texte;
Wich is highly unfavorable, since the browser has to parse and rebuild, whatever there already is in divCategorie.innerHTML.
Just appending the new Markup would be better.
long way short: maybe a good hack would be to insert some hidden node as a placeholder (so you kan keep order, although the AJAX-requests may return in a different order) and replace that node with the real content, as soon as it arrives.
Kind of like this:
addAptitudeField : function(currentAutocompleteField, idChamp) {
var currentAutocompleteFieldBind = currentAutocompleteField;
var idChampBind = idChamp;
//this is done immediately, and therefore preserves the order of the loop,
//without any delays/timeouts
var placeholder = document.createElement("div");
placeholder.className = "placeholder";
placeholder.style.display = "none";
divCategorie.appendChild(placeholder);
window.setTimeout(function() {
// Code ...
var paramDwr = {};
var newDivName = "div" + idChamp + lastValueId;
paramDwr[attributs.r_divId] = newDivName;
paramDwr[attributs.r_currentValue] = currentValue;
paramDwr[attributs.r_hiddenIdsField] = hiddenIdsField.id;
paramDwr[attributs.r_lastValueId] = lastValueId;
paramDwr[attributs.r_itemmod] = nbAptitudesCat % 2 == 0;
// setTimeout ( RepertoireDwr.ligneSuppEtSpanMessage, 1000 ) doesn't work
RepertoireDwr.ligneSuppEtSpanMessage(paramDwr, function(ajaxPage) {
//convert the passed text into a DocumentFragment
var frag = fragment(ajaxPage.texte);
//replacing the placeholder with the fragment
divCategorie.insertBefore(frag, placeholder);
divCategorie.removeChild(placeholder);
aptitudeAvecDetail.remetsValeursStockees();
var btnSuppression = $(newDivName).getElementsByTagName('img')[0];
//this is also pretty horrible to me:
btnSuppression.setAttribute("onclick", "formulaireFiche.updateCSS('" + newDivName + "');" + btnSuppression.getAttribute("onclick") + "fiche.updateCategorieSuppressionAptLieeUo(\'divCat" + currentCategorie + "\');"); });
}
}, 400);
}
I think you should do some major refactoring. And take a look into Promises.
// * -> DocumentFragment
//strings/primitives are parsed as HTML-markup,
//null / undefined is ignored
//Arraylike structures are parsed recursively
var fragment = (function(container){
return function(src){
return reducer(document.createDocumentFragment(), src);
}
function reducer(frag, node){
var i, len, fc, c, r;
if(node === Object(node)){
if("nodeType" in node){
//dom nodes
frag.appendChild(node);
}else{
//Arraylike structures, like NodeLists or jQuery-Objects, or just plain Arrays
for(i = 0, len = ("length" in node && node.length)|0, r = reducer; i < len; (i in node) && r(frag, node[i]));
}
}else if(node != null) {
//strings (all primitives)
for((c=container).innerHTML = node; fc = c.firstChild; frag.appendChild(fc));
}
return frag;
}
})(document.createElement("div"));

I can't get any closure so to speak

I know this kind of question has been asked a thousand times before, I read a ton of posts on this but I still can't wrap my head around it. Tried many examples without success on my own before posting here.
I'm basically trying to return images from different folders but I need to process the images from each directory separately in a specific way. I am not very familiar with json and ajax in general so this might be why I don't understand this too well.
Anyhow, my idea was to simply create a for loop and then for each directory, get the images via ajax and deal with them.
Obviously this ain't working as I expected and I read somewhere that I need a javascript "closure" to get this to work but it never works. Here is my basic code without closure:
$.getJSON('/img/content/galleries/', function(directories) {
for (var dirnum = 2; dirnum < directories.length - 1; dirnum++) {
var folder = '/img/content/galleries/' + directories[dirnum] + '/';
$.ajax({
url: folder,
success: function(data) {
$("#gallery").text("");
$(data).find("a").attr("href", function(i, val) {
if (val.match(/\.jpg|\.png|\.gif/)) {
$("#gallery").append("<img src='" + folder + val + "'>");
}
}); // end data.find
} // end success
}); // end ajax
} // end for loop
}); // end getJSON
This code runs but always give me the results of gallery2 before gallery1 (the name of my directories) and then gives an error saying it can't find images from gallery1 inside the gallery2 folder...
If anybody can help me insert some kind of closure in here that would be great. A few hours already wasted with no results so far. I just don't get that concept I guess.
Also note that I previously get the "directories" values from a php file in the parent folder of gallery1 and gallery 2 that has that code in it:
<?php
$directories = scandir('.');
header('Content-Type: application/json');
echo json_encode($directories);
?>
Or if you guys think there is a simpler way to approach this in javascript I'm all ears! I know I could have done it a different way with php intermixed with some javascript but I wanted to use javascript only here.
Thanks a bunch in advance.
Erick P.

Major flaw is each request empties the container ... so only content from last request received will be displayed.
Fix that by emptying container before the request loop starts
You can't control order of requests received ... so if order is important will need to use promises for the requests in order to make sure data is populated in correct order
$.getJSON('/img/content/galleries/', function(directories) {
//empty container before starting request loop
$("#gallery").empty();
for (var dirnum = 2; dirnum < directories.length - 1; dirnum++) {
// wrap ajax in IIFE closure
(function(dirnum){
var folder = '/img/content/galleries/' + directories[dirnum] + '/';
$.ajax({
url: folder,
success: function(data) {
//$("#gallery").text("");// move up above loop
$(data).find("a").attr("href", function(i, val) {
if (val.match(/\.jpg|\.png|\.gif/)) {
$("#gallery").append("<img src='" + folder + val + "'>");
}
}); // end data.find
} // end success
}); // end ajax
})(dirnum);//end closure in for loop
} // end for loop
}); // end getJSON
Not quite sure why you start at third index for dirnum....assume you have unwanted paths in the directories array. Would be cleaner to filter those at server

Thanks to Charlie for the help! I fixed it via the closure as everyone told me:
$.getJSON('/img/content/galleries/', function(directories) {
$("#gallery").text("");
for (var dirnum = 2; dirnum < directories.length - 1; dirnum++) {
(function(dirnum) {
var folder = '/img/content/galleries/' + directories[dirnum] + '/';
$.ajax({
url: folder,
success: function(data) {
$(data).find("a").attr("href", function(i, val) {
if (val.match(/\.jpg|\.png|\.gif/)) {
$("#gallery").append("<img src='" + folder + val + "'>");
}
}); // end data.find
} // end success
}); // end ajax
})(dirnum);
} // end for loop
}); // end getJSON
Charlie I'll try your solution also to check as another alternative. Thanks again!
Erick

Passing result from .getJSON() to another function results in undefined

Good day everyone,
I am pulling back some data from a database (via a PHP script) using jQuery's .getJSON() method. This is all well and good, the data comes back just fine and as expected. The problem occurs when I try to pass the data to a secondary function, no matter how I try to access the values of that data they come back as undefined. I have a feeling I am overlooking something very simple but after a lot of trial and error I come to SO asking for an extra set of eyes.
Here is a simple example of the JavaScript code.
function fnCheck_Vis(Row, sField, sMode)
{
sField = sField+"_vis";
sTest = Row.sField.val();
alert(sTest); // Comes back as undefined.
}
$(document).ready(function()
{
$("#btnSearch").click(function()
{
$("#divResults").empty();
var ssearch = $("#ssearch").val();
var i = 0;
$.getJSON("get_results.php?keywords=" + ssearch,
function(Data)
{
var iRec = 0;
$.each(Data, function(i, Row)
{
fnCheck_Vis(Row, "slinkpic1", "Int");
var content = Row.slast;
$("#divResults").append(content);
iRec++;
});
alert(iRec + " records retrieved using AJAX.");
});
});
});
The first piece of the fnCheck_Vis() function works fine and "_vis" is appended to the field name, this is proper behavior. No matter how I try to access that member in the dataset (Row) I can not get a value back.
I really appreciate any insight that can be given on this issue.
Thanks,
Nicholas

It looks like you want to access the property of Row whose name is stored in sField, not its actual sField property. Try:
function fnCheck_Vis(Row, sField, sMode)
{
sField = sField + "_vis";
var sTest = Row[sField];
alert(sTest);
}