Add throbber to jQuery post() - javascript

I am displaying a throbber when I do an ajax post. Below is how I am doing it. I would like to make the code more concise. Could I extend $.post to do so? Other options? Thanks
//myThrobber is an object that displays a throbber in the center of the page
myThrobber.start();
$.post('somePage.php',myData,function (json){
myThrobber.stop();
//do whatever
},'json');

Here is how I'd write a postThrob function wrapped around $.post.
$.fn.postThrob = function (throbber, url, data, callback) {
throbber.start();
$.post(url, data, function (response) {
callback(response);
throbber.stop();
});
};
So now you can use $.postThrob instead of $.post. Just pass your throbber object in as the first argument.
If you don't want to pass your throbber obj in, you can use a global variable, though less preferable. Just don't create the object inside the function itself.
I still don't see much value in doing this though ;(

Related

Calling function by string not working

I'm trying to write a js function that triggers another, variable, function when complete. I figured I could do this by passing the second function's name as a string, but I can't get it to work. Here's my code:
logMeIn('likeThisPost');
function logMeIn(callBack) {
//First function content
$.post("/ajaxurl/",
{
login_id: login_id,
intent: 'login'
},
function(){
console.log('Logged in, refreshing header');
$.post("/secondajaxurl/",{},
function(data){
//success
if(typeof callBack!=='undefined') {
window[callBack]();
}
}
);
}
);
});
}
This should, according to my thinking, run likeThisPost after successfully completing both ajax calls in logMeIn, but instead I get this error:
window[callBack] is not a function
The function I'm calling on success definitley exists, and besides which, it doesn't look like it's even trying to call that function, but it's treating callBack as literal rather than a string.
I'm using jQuery and have everything wrapped in a $. Where am I going wrong?
With thanks to Jonas W and Rory McCrossan, the answer was to change the passed function to the function name, rather than a string, and then call the function directly rather than using window.
So logMeIn(likeThisPost) instead of logMeIn("likeThisPost") and callBack(); rather than window[callBack]();.
Thanks!

Enable binding breaks when observable array updated via Ajax success callback

http://jsfiddle.net/FZ6K6/24/
I have a button (Remove inputs) with enable and css bindings that are returned when an observable array contains more than 2 items.
<button data-bind="click: removeInput, enable: Integers().length >2, css { red: Integers().length >2 }">Remove Input</button>
I also have a function (loadIntegerSorter) that sets the observable array to contain 2 items.
self.loadIntegerSorter = function () {
self.Integers([new integer(0, 0, 0), new integer(0, 0, 0)]);
};
I also have a save function that submits via ajax. Within the success callback, loadIntegerSorter is called.
success: function (result) {
if (result.Status == "success") {
isvm.loadSortedIntegers();
}
}
However, this seems to break the enable binding. The CSS binding behaves as expected with the array items = 2. But the Enable binding does not. I can run loadIntegerSorter outside of the Ajax function successfully so I suppose this is a synchronization problem but I don't know what the solution is.
The fiddle I've linked to doesn't fully demonstrate the problem because it depends on making a genuine Ajax request. But I hope it shows enough to understand.
Elaboration:
This results in the expected behaviour from the enable binding:
self.save = function () {
self.isloading();
};
But this doesn't:
self.save = function () {
$.ajax("/Home/Index", {
data: ko.toJSON(self.integerSorter),
cache: false,
type: "post",
contentType: "application/json",
context: self,
success: function (result) {
this.isloading();
}
});
};
And nor does this:
self.save = function () {
self.isloading();
$.ajax("/Home/Index", {
data: ko.toJSON(self.integerSorter),
cache: false,
type: "post",
contentType: "application/json",
context: self,
success: function (result) {
}
});
};
Whatever the cause of the problem, it seems to be related to the ajax call.
1)
Inside of your self.save function you're calling
self.isLoading(true);
Which yields
TypeError: 'undefined' is not a function (evaluating
'self.isLoading(true)')
telling you that self.isLoading is not declared anywhere in your code. This will break code execution even before the ajax request is sent.
2)
Same as 1) but this time for self.msgbox.status(). Undeclared: will break your code.
3)
The function self.loadIntegerSorter appears as self.loadSortedIntegers in the success function. Also, the self.save function appears declared two times. The second one will ovverride the first, but I guess the first one is there just in the fiddle.
4)
Inside of the success function, result.Status doesn't have any sense. You must understand that result is just a string of plain text, accessing the Status property of a string will result in an error. Perhaps you expect the response to be a JSON object with a Status property? If that is the case, you have to deserialize the string either by yourself (JSON.parse(response)) or by telling jQuery to do that for you (replace $.ajax with $.getJSON).
However, it may also be that you're not receiving any JSON back and you just wanted to access the response status, assuming you could do it that way. You can't. Being inside of a success function, you already know that your request has been successfully sent and a response received. No need to check it again.
5)
You're calling the loadSortedIntegers() method on the variable isvm. That's a totally wrong approach, even if it should work now it may cause huge troubles in the future. isvm is a global variable you use to contain an instance of your viewModel. The success function is contained in the viewModel itself, you should access it's own methods with this or self. A class should not access an instance of itself with a global variable. Question: how can I make this and/or self available in the success function? this can be reached by setting the context property to your $.ajax object. Exactly as you write success: function(){} you should write, just before that, context: this or, in your case, context: self.
Do that, and then just change the success function contents with this.loadSortedIntegers().
I've took the liberty to make some edits to your fiddle. Take your time to examine the difference here and to run it here.
Try to use valueHasMutated to push update for observable directly:
self.loadIntegerSorter = function () {
self.Integers([new integer(0, 0, 0), new integer(0, 0, 0)]);
self.Integers.valueHasMutated();
};

Can we save jquery POST/GET callback function's data and status in a variable for further use?

I want to save the value of data and status in a variable and use it after the closing brackets of jquery GET/POST function.But alert comes only when it is inside .get braces.
$(document).ready(function(){
$.get("demo_test.asp",function(data,status){
v = data;
});
alert("Data:"+v);
});
As Jasper said, your alert is being triggered before the request is complete (async!). So, you have two options:
Do your logic inside the callback:
$.get("demo_test.asp",function(data,status){
v = data;
alert("Data:"+v);
//Process stuff here
});
Or pass the received data onto another function and work with it there
$.get("demo_test.asp",function(data,status){
v = data;
doStuff(v);
});
function doStuff(param) {
console.log(param);
}
You're absolutely correct; the code is working as it should... here's why:
The page loads and starts running code, it then hits the .get command and then keeps running, obviously making it to the 'alert' you have next. Since the .get function is still working on fetching the data before your page makes it to the 'alert' part... there's nothing to prompt.
You might want to string things together after the .get, using deferred objects. Look into: http://api.jquery.com/deferred.always/
This is a way of tacking on another function inside of the one fetching your data, so they depend on each other.
Simple answer, yes, you can store the data in a global variable and access it elsewhere. However, you must wait until it is ready.
The better way to do it is to instead store the jqXHR globally and simply add a done callback to it when you need to access the data.
var reqDemoTest = $.get(...);
//... some time later...
reqDemoTest.done(function(data){
console.log(data);
});

How does this javascript work?

I'm a javascript noob, and I don't understand why this works:
$().load('/my/url/', {my:data, more:data}, jsFunc());
function jsFunc()
{
$("#myid").val("yep");
}
But not this:
$().load('/my/url/', {my:data, more:data}, function() {jsFunc()});
function jsFunc()
{
$("#myid").val("yep");
}
I tried an $.ajax instead of $.load with the same result. I will be passing the response data to jsFunc() and that is why I need jsFunc() inside the function. I'm sure it is something simple I'm just not very experienced with javascript. Thanks.
Thanks again for all the help. I decided to use $.post because it works best for the situation but now I'm having trouble with the response data. My code looks like this:
$.post('/my/url/', {my:data, more:data}, function(data) {
var strung = JSON.stringify(data)
var parse = jQuery.parseJSON(strung)
console.log(parse.some);}, 'json');
I'm logging to the console to see what is coming back for now and I will add the callback when I see the correct value logged. The process I got from the jQuery api page, but it will only log undefined. When I change parse.some to parse the console log will display the objects and I can select an element and see the correct key:value pair. Any help would be sweet.
Neither works. The first one appears to work, because you call the function jsFunc immediately, it doesn't wait for any response.
If you create an empty jQuery object using $() and use the load method on that, it won't call the server because there is no element where it can put the result.
To specify the callback function you either use the name of a function:
$('#someElement').load('/my/url/', {my:data, more:data}, jsFunc);
or a function expression:
$('#someElement').load('/my/url/', {my:data, more:data}, function() { jsFunc(); });
The first code block will simply call jsFunc() and return the results as the parameter to the load(..) method, which is odd because that parameter is supposed to be a callback function to fire when the load completes, but that works? The callback syntax is more in keeping with the second example (the one I believe you stated doesn't work).
Answer to my second part:
My returned JSON data consisted of many objects, so I had to specify the index and the key to get the value to return.

How to utilize generic AJAX call with multiple success functions

I am making an ajax call that returns XML. This XML needs to be handled differently based upon the section of the page within the site the user is on. Thus, I would like to implement 1 ajax function that makes the calls, and has a variable success function... I'm sure it is simple but I've searched for a while and cannot figure it out..
function makeAjaxCall(variableSuccessFunction) {
$.ajax.... (ajax stuff goes here)...
success: variableSuccessFunction(xml)
}
function ViewOne(xml) {
//take the XML and update the dom as appropriate
}
function ViewTwo(xml) {
//take the XML and update the dom as appropriate
}
$(document).ready(function() {
//be able to call either one of these functions
makeAjaxCall(ViewOne);
makeAjaxCall(ViewTwo);
}
You've basically got it! Just one tweak:
function makeAjaxCall(variableSuccessFunction) {
$.ajax.... (ajax stuff goes here)...
success: variableSuccessFunction // no (xml)
}
You're passing around function references. success is passed a reference to variableSuccessFunction (whatever that may be) and will call it just like it would if you had supplied an anonymous function to it. No need to invoke it inside of makeAjaxCall.

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