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How to pass variable from one JS file to the other from within a deferred function

I'm trying to call json object in another JS file but there seems to be a timing issue. So I put a setTimeout below but the setTiemout runs twice, first with the object populated, then again with the object undefined and then undefined the passed to the second JS file. I also tried clearTimeout but then it didn't run at all. Then I tried a boolean but it still ran twice. I think the issue might be cause of the deferred, is there any way around this?
var json = {};
$('.submit').on('click', function (e) {
e.preventDefault();
var input = $('.url-input');
var def = $.Deferred();
$.ajax({
type: "GET",
url: $(input).val(),
data: input.serialize(), // serializes the form's elements.
success: function(data) {
var category;
$(data).find('a[href*="categories"]').filter(function(){
var data = $(this);
category = data.text().trim();
json.category = category;
});
def.resolve();
return def.promise;
}
}).then(function () {
$('.cust-viz.viz-2').html('<iframe class="bubble_chart" src="bubble_chart.html" height="500"></iframe>');
if (json.category) {
hideShowViz('show');
}
});
});
}
setTimeout(function () {
json = json;
}, 5000);
based on answers, I did
var json ={};
$('.submit').on('click', function (e) {
e.preventDefault();
var input = $('.url-input');
$.ajax({
type: "GET",
url: $(input).val(),
data: input.serialize(), // serializes the form's elements.
}).then(function (data) {
var category;
$(data).find('a[href*="categories"]').filter(function(){
var data = $(this);
category = data.text().trim();
json.category = category;
});
if (json.category) {
$('.cust-viz.viz-2').html('<iframe class="bubble_chart" src="bubble_chart.html" height="500"></iframe>');
hideShowViz('show');
}
});
});
}
Still returning empty.

There are multiple issues with the code.
Regarding timing, you are likely to have issues with this pattern ...
$.ajax({
...
success: fnA
})
.then(fnB);
... especially if fnB is dependent on something done by fnA.
In practice, it's never good to mix a success handler written as an $.ajax() option with one written as a .then() callback.
So refactor as follows :
$.ajax({
...
})
.then(fnA)
.then(fnB);
Now,
if fnA is asynchronous, it must return a promise to inhibit progress to fnB until that promise resolves.
if fnA is wholly synchronous, as appears to be the case, you can return a value or , more typically, you would merge fnA with fnB.
Note: A success handler written as an $.ajax() option does not possess the same power, and that's the reason why we don't mix success: fn with .then().
$.ajax({
...
})
.then(fnAB);
With those rules in mind, you should be able to better debug the other issues.

Javascript When and Done Function use

I am trying to call two different functions in third function but one after the other.One function has ajax call, whose values are used in other function. it is step by step process. I don't want to use one into the other.
function f1()
{
// ajax call
return r1
}
function f2(r2)
{
// do some of the work based on r2
}
function f3()
{
$.when(f1()).done(function(data){
f2(data)
});
}
I also tried with $.when().then(); but still of no use.
Thanks, in advance.
UPDATE :- Below is the answer for my Question based on solution provide by #dreamweiver.
var json_data = '';
function f1()
{
$.ajax({
url: "test.php",
method: "POST",
async : false,
data: { },
success:function(data){
json_data = eval(data);
}
});
}
function f2(t)
{
console.log("values is "+t);
}
function f3()
{
$.when(f1()).done(function(){
f2(json_data);
});
}
Thanks everyone for your feedbacks.

Try this way, I have tested locally and it works perfectly
function deferredCalls () {
var jsonData = '';
var f1 = function ()
{
// ajax call
$.ajax({
url: "test.html",
method: "POST",
data: { id : menuId }
}).done(function(data) {
jsonData = data; //set the data
});
}
var f2 = function (data)
{
// do some of the work based on data
if(!!data){
//process the data
}
}
$.when(f1).done(function(){
f2(jsonData);
});
}
f1 function is called first which would in turn make a ajax request and return data on success, which is set to a function scope variable jsonData. Once this process is completed, f2 would be called which will start using jsonData, which is nothing but the data received from f1 function call.

This should be working:
function f1() {
// Or some other Ajax request that returns a promise
return $.getJSON('path/to/your/service');
}
function f2(r2) {
// ...
}
f1().done(f2);

How can i excute a function after all ajax requests complete? [duplicate]

How do I make a function wait until all jQuery Ajax requests are done inside another function?
In short, I need to wait for all Ajax requests to be done before I execute the next. But how?

jQuery now defines a when function for this purpose.
It accepts any number of Deferred objects as arguments, and executes a function when all of them resolve.
That means, if you want to initiate (for example) four ajax requests, then perform an action when they are done, you could do something like this:
$.when(ajax1(), ajax2(), ajax3(), ajax4()).done(function(a1, a2, a3, a4){
// the code here will be executed when all four ajax requests resolve.
// a1, a2, a3 and a4 are lists of length 3 containing the response text,
// status, and jqXHR object for each of the four ajax calls respectively.
});
function ajax1() {
// NOTE: This function must return the value
// from calling the $.ajax() method.
return $.ajax({
url: "someUrl",
dataType: "json",
data: yourJsonData,
...
});
}
In my opinion, it makes for a clean and clear syntax, and avoids involving any global variables such as ajaxStart and ajaxStop, which could have unwanted side effects as your page develops.
If you don't know in advance how many ajax arguments you need to wait for (i.e. you want to use a variable number of arguments), it can still be done but is just a little bit trickier. See Pass in an array of Deferreds to $.when() (and maybe jQuery .when troubleshooting with variable number of arguments).
If you need deeper control over the failure modes of the ajax scripts etc., you can save the object returned by .when() - it's a jQuery Promise object encompassing all of the original ajax queries. You can call .then() or .fail() on it to add detailed success/failure handlers.

If you want to know when all ajax requests are finished in your document, no matter how many of them exists, just use $.ajaxStop event this way:
$(document).ajaxStop(function () {
// 0 === $.active
});
In this case, neither you need to guess how many requests are happening in the application, that might finish in the future, nor dig into functions complex logic or find which functions are doing HTTP(S) requests.
$.ajaxStop here can also be bound to any HTML node that you
think might be modified by requst.
Update:
If you want to stick with ES syntax, then you can use Promise.all for known ajax methods:
Promise.all([ajax1(), ajax2()]).then(() => {
// all requests finished successfully
}).catch(() => {
// all requests finished but one or more failed
})
An interesting point here is that it works both with Promises and $.ajax requests.
Here is the jsFiddle demonstration.
Update 2:
Yet more recent version using async/await syntax:
try {
const results = await Promise.all([ajax1(), ajax2()])
// do other actions
} catch(ex) { }

I found a good answer by gnarf my self which is exactly what I was looking for :)
jQuery ajaxQueue
//This handles the queues
(function($) {
var ajaxQueue = $({});
$.ajaxQueue = function(ajaxOpts) {
var oldComplete = ajaxOpts.complete;
ajaxQueue.queue(function(next) {
ajaxOpts.complete = function() {
if (oldComplete) oldComplete.apply(this, arguments);
next();
};
$.ajax(ajaxOpts);
});
};
})(jQuery);
Then you can add a ajax request to the queue like this:
$.ajaxQueue({
url: 'page.php',
data: {id: 1},
type: 'POST',
success: function(data) {
$('#status').html(data);
}
});

Use the ajaxStop event.
For example, let's say you have a loading ... message while fetching 100 ajax requests and you want to hide that message once loaded.
From the jQuery doc:
$("#loading").ajaxStop(function() {
$(this).hide();
});
Do note that it will wait for all ajax requests being done on that page.

NOTE: The above answers use functionality that didn't exist at the time that this answer was written. I recommend using jQuery.when() instead of these approaches, but I'm leaving the answer for historical purposes.
-
You could probably get by with a simple counting semaphore, although how you implement it would be dependent on your code. A simple example would be something like...
var semaphore = 0, // counting semaphore for ajax requests
all_queued = false; // bool indicator to account for instances where the first request might finish before the second even starts
semaphore++;
$.get('ajax/test1.html', function(data) {
semaphore--;
if (all_queued && semaphore === 0) {
// process your custom stuff here
}
});
semaphore++;
$.get('ajax/test2.html', function(data) {
semaphore--;
if (all_queued && semaphore === 0) {
// process your custom stuff here
}
});
semaphore++;
$.get('ajax/test3.html', function(data) {
semaphore--;
if (all_queued && semaphore === 0) {
// process your custom stuff here
}
});
semaphore++;
$.get('ajax/test4.html', function(data) {
semaphore--;
if (all_queued && semaphore === 0) {
// process your custom stuff here
}
});
// now that all ajax requests are queued up, switch the bool to indicate it
all_queued = true;
If you wanted this to operate like {async: false} but you didn't want to lock the browser, you could accomplish the same thing with a jQuery queue.
var $queue = $("<div/>");
$queue.queue(function(){
$.get('ajax/test1.html', function(data) {
$queue.dequeue();
});
}).queue(function(){
$.get('ajax/test2.html', function(data) {
$queue.dequeue();
});
}).queue(function(){
$.get('ajax/test3.html', function(data) {
$queue.dequeue();
});
}).queue(function(){
$.get('ajax/test4.html', function(data) {
$queue.dequeue();
});
});

A little workaround is something like this:
// Define how many Ajax calls must be done
var ajaxCalls = 3;
var counter = 0;
var ajaxCallComplete = function() {
counter++;
if( counter >= ajaxCalls ) {
// When all ajax calls has been done
// Do something like hide waiting images, or any else function call
$('*').css('cursor', 'auto');
}
};
var loadPersons = function() {
// Show waiting image, or something else
$('*').css('cursor', 'wait');
var url = global.ctx + '/loadPersons';
$.getJSON(url, function(data) {
// Fun things
})
.complete(function() { **ajaxCallComplete();** });
};
var loadCountries = function() {
// Do things
var url = global.ctx + '/loadCountries';
$.getJSON(url, function(data) {
// Travels
})
.complete(function() { **ajaxCallComplete();** });
};
var loadCities = function() {
// Do things
var url = global.ctx + '/loadCities';
$.getJSON(url, function(data) {
// Travels
})
.complete(function() { **ajaxCallComplete();** });
};
$(document).ready(function(){
loadPersons();
loadCountries();
loadCities();
});
Hope can be useful...

javascript is event-based, so you should never wait, rather set hooks/callbacks
You can probably just use the success/complete methods of jquery.ajax
Or you could use .ajaxComplete :
$('.log').ajaxComplete(function(e, xhr, settings) {
if (settings.url == 'ajax/test.html') {
$(this).text('Triggered ajaxComplete handler.');
//and you can do whatever other processing here, including calling another function...
}
});
though youy should post a pseudocode of how your(s) ajax request(s) is(are) called to be more precise...

jQuery allows you to specify if you want the ajax request to be asynchronous or not. You can simply make the ajax requests synchronous and then the rest of the code won't execute until they return.
For example:
jQuery.ajax({
async: false,
//code
});

As other answers mentioned you can use ajaxStop() to wait until all ajax request are completed.
$(document).ajaxStop(function() {
// This function will be triggered every time any ajax request is requested and completed
});
If you want do it for an specific ajax() request the best you can do is use complete() method inside the certain ajax request:
$.ajax({
type: "POST",
url: "someUrl",
success: function(data) {
// This function will be triggered when ajax returns a 200 status code (success)
},
complete: function() {
// This function will be triggered always, when ajax request is completed, even it fails/returns other status code
},
error: function() {
// This will be triggered when ajax request fail.
}
});
But, If you need to wait only for a few and certain ajax request to be done? Use the wonderful javascript promises to wait until the these ajax you want to wait are done. I made a shortly, easy and readable example to show you how does promises works with ajax. Please take a look to the next example. I used setTimeout to clarify the example.
// Note:
// resolve() is used to mark the promise as resolved
// reject() is used to mark the promise as rejected
$(document).ready(function() {
$("button").on("click", function() {
var ajax1 = new Promise((resolve, reject) => {
$.ajax({
type: "GET",
url: "https://miro.medium.com/max/1200/0*UEtwA2ask7vQYW06.png",
xhrFields: { responseType: 'blob'},
success: function(data) {
setTimeout(function() {
$('#image1').attr("src", window.URL.createObjectURL(data));
resolve(" Promise ajax1 resolved");
}, 1000);
},
error: function() {
reject(" Promise ajax1 rejected");
},
});
});
var ajax2 = new Promise((resolve, reject) => {
$.ajax({
type: "GET",
url: "https://cdn1.iconfinder.com/data/icons/social-media-vol-1-1/24/_github-512.png",
xhrFields: { responseType: 'blob' },
success: function(data) {
setTimeout(function() {
$('#image2').attr("src", window.URL.createObjectURL(data));
resolve(" Promise ajax2 resolved");
}, 1500);
},
error: function() {
reject(" Promise ajax2 rejected");
},
});
});
var ajax3 = new Promise((resolve, reject) => {
$.ajax({
type: "GET",
url: "https://miro.medium.com/max/632/1*LUfpOf7teWvPdIPTBmYciA.png",
xhrFields: { responseType: 'blob' },
success: function(data) {
setTimeout(function() {
$('#image3').attr("src", window.URL.createObjectURL(data));
resolve(" Promise ajax3 resolved");
}, 2000);
},
error: function() {
reject(" Promise ajax3 rejected");
},
});
});
Promise.all([ajax1, ajax2, ajax3]).then(values => {
console.log("We waited until ajax ended: " + values);
console.log("My few ajax ended, lets do some things!!")
}, reason => {
console.log("Promises failed: " + reason);
});
// Or if you want wait for them individually do it like this
// ajax1.then(values => {
// console.log("Promise 1 resolved: " + values)
// }, reason => {
// console.log("Promise 1 failed: " + reason)
// });
});
});
img {
max-width: 200px;
max-height: 100px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button>Make AJAX request</button>
<div id="newContent">
<img id="image1" src="">
<img id="image2" src="">
<img id="image3" src="">
</div>

If you need something simple; once and done callback
//multiple ajax calls above
var callback = function () {
if ($.active !== 0) {
setTimeout(callback, '500');
return;
}
//whatever you need to do here
//...
};
callback();

Also you could use async.js.
I think its better than $.when because you can merge all kinds of asynchronous call that does not support promises out of the box like timeouts, SqlLite calls etc. and not just ajax requests.

On the basis of #BBonifield answer, I wrote a utility function so that semaphore logic is not spread in all the ajax calls.
untilAjax is the utility function which invokes a callback function when all the ajaxCalls are completed.
ajaxObjs is a array of ajax setting objects [http://api.jquery.com/jQuery.ajax/].
fn is callback function
function untilAjax(ajaxObjs, fn) {
if (!ajaxObjs || !fn) {
return;
}
var ajaxCount = ajaxObjs.length,
succ = null;
for (var i = 0; i < ajaxObjs.length; i++) { //append logic to invoke callback function once all the ajax calls are completed, in success handler.
succ = ajaxObjs[i]['success'];
ajaxObjs[i]['success'] = function(data) { //modified success handler
if (succ) {
succ(data);
}
ajaxCount--;
if (ajaxCount == 0) {
fn(); //modify statement suitably if you want 'this' keyword to refer to another object
}
};
$.ajax(ajaxObjs[i]); //make ajax call
succ = null;
};
Example: doSomething function uses untilAjax.
function doSomething() {
// variable declarations
untilAjax([{
url: 'url2',
dataType: 'json',
success: function(data) {
//do something with success data
}
}, {
url: 'url1',
dataType: 'json',
success: function(data) {
//do something with success data
}
}, {
url: 'url2',
dataType: 'json',
success: function(response) {
//do something with success data
}
}], function() {
// logic after all the calls are completed.
});
}

I highly recommend using $.when() if you're starting from scratch.
Even though this question has over million answers, I still didn't find anything useful for my case. Let's say you have to deal with an existing codebase, already making some ajax calls and don't want to introduce the complexity of promises and/or redo the whole thing.
We can easily take advantage of jQuery .data, .on and .trigger functions which have been a part of jQuery since forever.
Codepen
The good stuff about my solution is:
it's obvious what the callback exactly depends on
the function triggerNowOrOnLoaded doesn't care if the data has been already loaded or we're still waiting for it
it's super easy to plug it into an existing code
$(function() {
// wait for posts to be loaded
triggerNowOrOnLoaded("posts", function() {
var $body = $("body");
var posts = $body.data("posts");
$body.append("<div>Posts: " + posts.length + "</div>");
});
// some ajax requests
$.getJSON("https://jsonplaceholder.typicode.com/posts", function(data) {
$("body").data("posts", data).trigger("posts");
});
// doesn't matter if the `triggerNowOrOnLoaded` is called after or before the actual requests
$.getJSON("https://jsonplaceholder.typicode.com/users", function(data) {
$("body").data("users", data).trigger("users");
});
// wait for both types
triggerNowOrOnLoaded(["posts", "users"], function() {
var $body = $("body");
var posts = $body.data("posts");
var users = $body.data("users");
$body.append("<div>Posts: " + posts.length + " and Users: " + users.length + "</div>");
});
// works even if everything has already loaded!
setTimeout(function() {
// triggers immediately since users have been already loaded
triggerNowOrOnLoaded("users", function() {
var $body = $("body");
var users = $body.data("users");
$body.append("<div>Delayed Users: " + users.length + "</div>");
});
}, 2000); // 2 seconds
});
// helper function
function triggerNowOrOnLoaded(types, callback) {
types = $.isArray(types) ? types : [types];
var $body = $("body");
var waitForTypes = [];
$.each(types, function(i, type) {
if (typeof $body.data(type) === 'undefined') {
waitForTypes.push(type);
}
});
var isDataReady = waitForTypes.length === 0;
if (isDataReady) {
callback();
return;
}
// wait for the last type and run this function again for the rest of the types
var waitFor = waitForTypes.pop();
$body.on(waitFor, function() {
// remove event handler - we only want the stuff triggered once
$body.off(waitFor);
triggerNowOrOnLoaded(waitForTypes, callback);
});
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<body>Hi!</body>

I'm using size check when all ajax load completed
function get_ajax(link, data, callback) {
$.ajax({
url: link,
type: "GET",
data: data,
dataType: "json",
success: function (data, status, jqXHR) {
callback(jqXHR.status, data)
},
error: function (jqXHR, status, err) {
callback(jqXHR.status, jqXHR);
},
complete: function (jqXHR, status) {
}
})
}
function run_list_ajax(callback){
var size=0;
var max= 10;
for (let index = 0; index < max; index++) {
var link = 'http://api.jquery.com/ajaxStop/';
var data={i:index}
get_ajax(link,data,function(status, data){
console.log(index)
if(size>max-2){
callback('done')
}
size++
})
}
}
run_list_ajax(function(info){
console.log(info)
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script>

To expand upon Alex's answer, I have an example with variable arguments and promises. I wanted to load images via ajax and display them on the page after they all loaded.
To do that, I used the following:
let urlCreator = window.URL || window.webkitURL;
// Helper function for making ajax requests
let fetch = function(url) {
return $.ajax({
type: "get",
xhrFields: {
responseType: "blob"
},
url: url,
});
};
// Map the array of urls to an array of ajax requests
let urls = ["https://placekitten.com/200/250", "https://placekitten.com/300/250"];
let files = urls.map(url => fetch(url));
// Use the spread operator to wait for all requests
$.when(...files).then(function() {
// If we have multiple urls, then loop through
if(urls.length > 1) {
// Create image urls and tags for each result
Array.from(arguments).forEach(data => {
let imageUrl = urlCreator.createObjectURL(data[0]);
let img = `<img src=${imageUrl}>`;
$("#image_container").append(img);
});
}
else {
// Create image source and tag for result
let imageUrl = urlCreator.createObjectURL(arguments[0]);
let img = `<img src=${imageUrl}>`;
$("#image_container").append(img);
}
});
Updated to work for either single or multiple urls: https://jsfiddle.net/euypj5w9/

I found simple way, it using shift()
function waitReq(id)
{
jQuery.ajax(
{
type: 'POST',
url: ajaxurl,
data:
{
"page": id
},
success: function(resp)
{
...........
// check array length if not "0" continue to use next array value
if(ids.length)
{
waitReq(ids.shift()); // 2
)
},
error: function(resp)
{
....................
if(ids.length)
{
waitReq(ids.shift());
)
}
});
}
var ids = [1, 2, 3, 4, 5];
// shift() = delete first array value (then print)
waitReq(ids.shift()); // print 1

My solution is as follows
var request;
...
'services': {
'GetAddressBookData': function() {
//This is the primary service that loads all addressbook records
request = $.ajax({
type: "POST",
url: "Default.aspx/GetAddressBook",
contentType: "application/json;",
dataType: "json"
});
},
...
'apps': {
'AddressBook': {
'data': "",
'Start': function() {
...services.GetAddressBookData();
request.done(function(response) {
trace("ajax successful");
..apps.AddressBook.data = response['d'];
...apps.AddressBook.Filter();
});
request.fail(function(xhr, textStatus, errorThrown) {
trace("ajax failed - " + errorThrown);
});
Worked quite nicely. I've tried a lot of different ways of doing this, but I found this to be the simplest and most reusable. Hope it helps

Look at my solution:
1.Insert this function (and variable) into your javascript file:
var runFunctionQueue_callback;
function runFunctionQueue(f, index, callback) {
var next_index = index + 1
if (callback !== undefined) runFunctionQueue_callback = callback;
if (f[next_index] !== undefined) {
console.log(index + ' Next function avalaible -> ' + next_index);
$.ajax({
type: 'GET',
url: f[index].file,
data: (f[index].data),
complete: function() {
runFunctionQueue(f, next_index);
}
});
} else {
console.log(index + ' Last function');
$.ajax({
type: 'GET',
url: f[index].file,
data: (f[index].data),
async: false,
complete: runFunctionQueue_callback
});
}
}
2.Buil an array with your requests, like this:
var f = [
{file: 'file_path', data: {action: 'action', data: 'any_data}},
{file: 'file_path', data: {action: 'action', data: 'any_data}},
{file: 'file_path', data: {action: 'action', data: 'any_data}},
{file: 'file_path', data: {action: 'action', data: 'any_data}}
];
3.Create callback function:
function Function_callback() {
alert('done');
}
4.Call the runFunctionQueue function with parameters:
runFunctionQueue(f, 0, QuestionInsert_callback);
// first parameter: array with requests data
// second parameter: start from first request
// third parameter: the callback function

$.when doesn't work for me, callback(x) instead of return x worked as described here: https://stackoverflow.com/a/13455253/10357604

The below solution worked for me using $when
$.when(master.GetStateByName(stateName)).done(function(response) {
if (response) {
}
});
GetStateByName: function(stateName) {
return $.ajax({
type: 'POST',
url: getStatesByName + '?stateName=' + stateName,
async: false,
});
}

This is working for me
It's very simple
return $.ajax({
type: 'POST',
url: urlBaseUrl
data: {someData:someData},
dataType: "json",
success: function(resultData) {
}
});

Try this way. make a loop inside java script function to wait until the ajax call finished.
function getLabelById(id)
{
var label = '';
var done = false;
$.ajax({
cache: false,
url: "YourMvcActionUrl",
type: "GET",
dataType: "json",
async: false,
error: function (result) {
label='undefined';
done = true;
},
success: function (result) {
label = result.Message;
done = true;
}
});
//A loop to check done if ajax call is done.
while (!done)
{
setTimeout(function(){ },500); // take a sleep.
}
return label;
}

JQuery Deferred how to use resolve and promise to determine function end

I have a in an html page that I'd like to show a spinner on while a JQuery function is running. Since its asynchronous I am trying to use deferred to determine when the function completed
the code in the html page
var req = jslongfunc(value);
req.done(function( response){
spinner.stop();
});
The code in the JS page that contains jslongfunc
function jslongfunc() {
rdef = $.Deferred();
$.getJSON('mycode, function(data){
... do lots of stuff here ...
});
setTimeout(function () {
r.resolve();
}, 4500);
return r.promise();
The spinner seems to run for 4500 regardless of when the jslongfunc finished all its code. I know when it finishes because it draws something. I thought r would return and .done would execute if the function finished before the time out. What am I doing wrong?

Your promise is resolving only when your setTimeout function is calling r.resolve() after 4500ms. You need to call r.resolve() when all your stuff is done. Maybe something like this...
// function definition
var jslongfunc = function(defr) {
//... do lots of stuff here ...
defr.resolve();
}
// promise helper
var promise = function (fn) {
var dfd = $.Deferred(fn);
return dfd.promise();
}
// init the deferred by using the promise helper above and then attach 'done' callback to stop spinner
var rdef = promise(jslongfunc).done(function (response) {
spinner.stop();
}).fail(function (response) {
// handle promise failure.
});
Update
Well now that you put up your using $.getJSON you can do the following.
function jslongfunc(value) {
var jqxhr = $.getJSON(url, function (data) {
// THIS IS YOUR FIRST promise callback
// do some stuff with the json you just got
});
// return the promise
return jqxhr;
}
// now handle the spinner stoppage
jslongfunc(value).done(function () {
spinner.stop();
}).fail(function (data) {
// handle function failure here
});

Here is a little FIDDLE that I use to hit the Google financial API for stock quotes.
I've added the Ajax events beforesend, complete that turns some gears off and on (very short period of time for this call).
But it will probably give you a start.
Edit: Here's a second FIDDLE with more compact code.
JS
$('.putmehere1').hide();
var quotevalue;
var symboltopass = "NYSE:SDY";
$.ajax({
type: "GET",
url: "https://finance.google.com/finance/info",
async: false,
dataType: 'JSONP',
data: {
client: 'ig',
q: symboltopass
}
})
.done( function(data){
var stockInfo = data[0];
console.log( data[0] );
quotevalue = stockInfo.l;
$('.putmehere2').html( '#2 - ' + quotevalue);
});
$.ajax({
beforeSend: function(){
$('.putmehere1').show();
},
complete: function(){
$('.putmehere1').hide();
}
});

Passing different arguments to deferred.resolve() for different handlers

I'm trying to sync up multiple ajax callbacks using jQuery.Deferrd objects. Obviously jQuery.when handles this for you however my code is architected in such a way that the ajax requests aren't called in the same method. So for example this is the flow:
// A Button is clicked
// Module 1 requests a snippet of html and updates the DOM
// Module 2 requests a different snippet of html and updates the DOM
I need both Modules to update the DOM at the same time meaning I need to ensure the callbacks are run after both requests have returned.
Module 1 and Module 2 need to be able to exist without each other and should have no knowledge of one another so the requests can't be made together using $.when(doMod1Request(), doMod2Request()).then(function () { ... }) and the callbacks should be independent too.
I've therefore written a wrapper around ajax which adds the callbacks to a deferred object and in a similar way to $.when resolves the deferred object once the ajax requests have returned the same number of times as the number of callbacks on the deferred object.
My dilemma is however deferred.resolve() can only be called with one set of arguments so each callback get's the same value.
e.g.
var deferred = new $.Deferred();
deferred.done(function (response) {
console.log(response); // <div class="html-snippet-1"></div>
});
deferred.done(function (response) {
console.log(response); // <div class="html-snippet-1"></div>
});
deferred.resolve('<div class="html-snippet-1"></div>');
Whereas I'd want something like this:
var deferred = new $.Deferred();
deferred.done(function (response) {
console.log(response); // <div class="html-snippet-1"></div>
});
deferred.done(function (response) {
console.log(response); // <div class="html-snippet-2"></div>
});
deferred.resolve(['<div class="html-snippet-1"></div>', '<div class="html-snippet-2"></div>']);
Is this possible or am I going about this incorrectly?

I'd say this is perfectly valid. Assuming your independent modules, you would do (with two Promises):
doMod1Request().done(doMod1Update);
doMod2Request().done(doMod2Update);
Now, if you want to to execute the updates together and only if the two requests both succeeded, just write
$.when(doMod1Request(), doMod2Request()).done(function(mod1result, mod2result) {
doMod1Update(mod1result);
doMod2Update(mod2result);
});
This only gets ugly if you call your resolve functions with multiple arguments, as jQuery is a bit inconsistent there and does not really distinguish multiple arguments from one array argument.
To uncouple them with that publish-subscribe pattern you are using, I'd recommend the following:
function Combination() {
this.deferreds = [];
this.success = [];
this.error = [];
}
Combination.prototype.add = function(def, suc, err) {
this.deffereds.push(def);
this.success.push(suc);
this.error.push(err);
};
Combination.prototype.start = function() {
var that = this;
return $.when.apply($, this.deferreds).always(function() {
for (var i=0; i<that.deferreds.length; i++)
that.deferreds[i].done(that.success[i]).fail(that.error[i]);
// of course we could also call them directly with the arguments[i]
});
};
// Then do
var comb = new Combination();
window.notifyModules("something happened", comb); // get deferreds and handlers
comb.start();
// and in each module
window.listen("something happended", function(c) {
c.add(doRequest(), doUpdate, doErrorHandling);
});

Let's assume your modules look something like this :
var MODULE_1 = function() {
function getSnippet() {
return $.ajax({
//ajax options here
});
}
return {
getSnippet: getSnippet
}
}();
var MODULE_2 = function() {
function getSnippet() {
return $.ajax({
//ajax options here
});
}
return {
getSnippet: getSnippet
}
}();
Don't worry if your modules are different, the important thing is that the getSnippet functions each return a jqXHR object, which (as of jQuery 1.5) implements the Promise interface.
Now, let's assume you want to fetch the two snippets in response to some event (say a button click) and do something when both ajax responses have been received, then the click handler will be something like this:
$("myButton").on('click', function(){
var snippets = [];
var promises_1 = MODULE_1.getSnippet().done(function(response){
snippets.push({
target: $("#div_1"),
response: response
});
});
var promise_2 = MODULE_2.getSnippet().done(function(response){
snippets.push({
target: $("#div_2"),
response: response
});
});
$.when(promise_1, promise_2).done(function() {
$.each(snippets, function(i, snippetObj) {
snippetObj.target.html(snippetObj.response);
});
});
});
Slightly more elaborate, and better if you have many similarly constructed modules to fetch many snippets, would be something like this:
$(function(){
$("myButton").on('click', function(){
var promises = [];
var snippets = [];
var modules = [MODULE_1, MODULE_2, MODULE_3 .....];
for (var i=1; i<=10; i++) {
promises.push(modules[i].getSnippet().done(function(response){
snippets.push({
target: $("#div_" + i),
response: response
};
}));
}
$.when.apply(this, promises).done(function() {
$.each(snippets, function(i, snippetObj) {
snippetObj.target.html(snippetObj.response);
});
});
});
});
As you can see, I've made heaps of assumptions here, but you should get some idea of how to proceed.

To ensure each callback is passed the appropriate arguments I've done the following:
var guid = 0,
deferreds = [];
window.request = function (url, deferred, success) {
var requestId = guid++;
if ($.inArray(deferred) === -1) {
deferreds.push(deferred);
$.extend(deferred, {
requestCount: 0,
responseCount: 0,
args: {}
});
}
deferred.requestCount++;
deferred
.done(function () {
// Corresponding arguments are passed into success callback using requestId
// which is unique to each request.
success.apply(this, deferred.args[requestId]);
});
$.ajax(url, {
success: function () {
// Store arguments on deferrds args obj.
deferred.args[requestId] = arguments;
deferred.responseCount++;
if (deferred.requestCount === deferred.responseCount) {
deferred.resolveWith(this);
}
}
});
};
So the arguments are managed through the closure. This allows me to ensure that both modules have no knowledge of each other and won't break if the other doesn't exist, e.g:
var MODULE_1 = function () {
$(".myButton").on('click', function() {
// Cross module communication is achieved through notifications.
// Pass along a new deferred object with notification for use in window.request
window.notify('my-button-clicked', new $.Deferred);
});
}();
var MODULE_2 = function () {
// run get snippet when 'my-button-clicked' notification is fired
window.listen('my-button-clicked', getSnippet);
function getSnippet (deferred) {
window.request('/module2', deferred, function () {
console.log('module2 success');
});
}
}();
var MODULE_3 = function () {
// run get snippet when 'my-button-clicked' notification is fired
window.listen('my-button-clicked', getSnippet);
function getSnippet (deferred) {
window.request('/module3', deferred, function () {
console.log('module3 success');
});
}
}();
The above allows each module to function independently meaning one will work without the other which loosely couples the code and because both MODULE_2 and MODULE_3 pass the same deferred object into window.request they will be resolved once both requests have successfully returned.
This was my final implementation:
https://github.com/richardscarrott/ply/blob/master/src/ajax.js