I have a jQuery deferred, which I an resolving like so:
deferredAction.resolve(returnArray);
and this is calling a callback like:
function someCallback(myArray) {
...
}
This works fine, the callback function receives the array. However I need to set the context of the callback function, so I used deferred.resolveWith like so:
deferredAction.resolveWith(someContext, returnArray);
The context is now being set correctly. However, it now seems as if the returnArray is being split up. My callback only receives the first item of the array.
Why is this happening, and how can I work around it?
The documentation states that you should pass the arguments in a single array. In your case:
deferredAction.resolveWith(someContext, [returnArray]);
I fixed this by putting square brackets around the return parameter:
deferredAction.resolveWith(someContext, [returnArray]);
Related
In short, I'm doing this:
function myHandler(a,b,c,d){
doStuffWithMyParams(a,b,c,d);
}
Then somewhere else:
jqueryElem.click(myHandler.bind(a,b,c,d));
When I do, some of the parameters passed (a,b) are read correctly. But the third (c) is a JQuery event object. I've also tried binding the args as an array. Then, the first param becomes the event object.
Totally perplexed here. Thanks in advance for any direction on this.
With the code myHandler.bind(a,b,c,d), the argument a is the context that bind() uses
So my handler is actually seeing this
function myHandler(b,c,d,event){
So I have a feeling you want
jqueryElem.click(myHandler.bind(this, a,b,c,d));
Building on what epascarello wrote, this should do the trick:
jqueryElem.click(myHandler.bind(this,[a,b,c,d]));
Not having the array might cause b to be treated as an eventHandler. Notice I used an array, but it could also be an object, for instance.
What I want:
I have a method which takes an int as as its only parameter, then I'm creating a list where each element will call the other function when clicked, the only thing I want to change is the number that each element passes when clicked.
What I have:
while(++i<e){
(...)
a.addEventListener('click',function(){selectUser(i)},false);
(...)
}
Of course, the obvious problem is that when called, it will always pass the final value of 'i'.
I need that each element passes the value that 'i' had when it was created.
ie; when i=3, I want it to translate into:
a.addEventListener('click',function(){selectUser(3)},false);
I guess it involves some method which returns another method with the actual value, but I'm not really sure how to implement it. I have very little experience with js.
Thanks in advance.
This is a classic problem of closures. You must enclose your event handler inside a closure function which keeps the state of your variable i. Like this...
while(++i<e){
(...)
(function(index){
a.addEventListener('click',function(){selectUser(index)},false);
})(i);
(...)
}
This way every call of the wrapping function will keep your state of the variable i and thereby giving you the right result.
You have to create a new function scope. You could do it the following way (call an anonymous function, which in turn returns a new function with the specified i.
a.addEventListener('click',(function(index) {
return function(){ selectUser(index) };
})(i),false);
From:
andrew whittakers example showing result numbers in a custom jquery autocomplete implementation
_response: function(contents){
$.ui.autocomplete.prototype._response.apply(this, arguments);
$(this.element).trigger("autocompletesearchcomplete", [contents]);
}
why [contents] and not contents ?
It's a requirement from jQuery's trigger function that the second parameter be an array (prior to 1.6.2), thus the wrapping to make it an array. From the trigger docs (emphasize by me):
$('#foo').bind('custom', function(event, param1, param2) {
alert(param1 + "\n" + param2);
});
$('#foo').trigger('custom', ['Custom', 'Event']);
The event object is always passed as the first parameter to an event
handler, but if additional parameters are specified during a
.trigger() call, these parameters will be passed along to the handler
as well. To pass more than one parameter, use an array as shown here.
As of jQuery 1.6.2, a single parameter can be passed without using an
array.
So as of 1.6.2, it's actually not necessary to wrap the single argument in an array.
If the function expects an array, then you put your one or more elements in square brackets. For example, trigger's function declaration is
.trigger( eventType [, extraParameters] )
Since you may want to give it more than one extra parameters, it accepts an array of them. If you have only one extra parameter to give, such as "contents" in your case, then you can put it into an array (or if you have just one parameter, you also can not put it into an array, as JQuery now accepts either way).
As Trinh pointed out its an array [content] with one element.
I dont know why but if you change it to content instead of [content] it will search for the query in the whole word.
If its [content] it will search only at the beginning.
I am having a function in javascript as
function add(v1,v2){
var add=v1+v2;
}
Now I am calling this function as below -
write.out(var param="1,2";);
write.out(window[add](param););
Using the above call, it's not working. What it does is it gives the complete string "1,2" as value to the first param(v1) of the function.
Its working if I call the function in following way -
write.out(var param1="1";);
write.out(var param2="2";);
write.out(window[add](param1,param2););
I want to achieve it using the first way where i can send the parameters as a comma separated string of parameters.
Can some one help me out how this can be done...
Thanks!!!
You can make usage of ECMAscripts .apply(), which calls a function and accepts an array of paramters.
window['add'].apply(null, param.split(','));
That way, we execute the add function, setting its context to null (you could also change that if you need) and pass in the two paramters. Since we need an Array, we call split() on the string before.
So basically, the above line is the same as
add(1,2);
Since you're haveing that function in the global context (window), we don't even need to write it that explicitly.
add.apply(null, param.split(','));
will just be fine.
Following example - the YoutubePlayer API
videoID.addEventListener('onStateChange', 'foo');
In the documentation they say, video.addEventListener(string: event, string: function).
That means the first parameter is the event (in my case onStateChange) and the second parameter is the function that is getting called when the even is triggered.
This youtube sample is just a good example, I've alredy had this question a few times before.
If the function to call is passed as a string, is there any chance to assign a a parameter to that function?
Imagine the function I want to call looks like this.
function foo(something) {
console.log(something).
}
It's obviously not possible to add a parameter to the function call is it? Like…
videoID.addEventListener('onStateChange', 'foo(videoID)');
Thank you for your information and answers.
You could do something like:
videoID.addEventListener('onStateChange', function()
{
foo(videoID);
});
...if I'm understanding you correctly.