CODEWITHSUNDEEP
javascriptajaxasynchronousprototype
BenM
BenM

Reputation: 4278

Does the use of prototyping in javascript have a negative effect on ajax calls and asynchronous code?

If I had the following object and prototyped functionality added on.

function Hello (input){
    this.input = input
}

Hello.prototype.ajaxcall = function(id){ 
    $.get("/ajax/method", {parameter:input}, function(data){ 
        $("#"id).html(data); 
    });
}

Forgive the syntax if not completely correct but what it should be doing is taking in an element id, performing an ajax call and assigning the ajax call result to the innerHTML of the id. Will the fact that the ajaxcall function is shared across all instances of an object cause any problems with regards to what data will be assigned to which id if for example 20 object were all created together and had this function called immediately?

If this is the case, does it make sense to put asyncronous methods inside the object constructor instead?

Upvotes: 0

Views: 47

Answers (3)

nnnnnn
nnnnnn

Reputation: 150070

This particular example would work. Your function makes no use of any instance variables, so it doesn't really make sense to declare it that way, but it makes even less sense to move it into the constructor. Still it will work because the id argument will not be shared between calls.

EDIT: So now that you've changed it so that it does use an instance variable you've got the syntax wrong, it needs to be

{parameter : this.input}

But aside from that it will still work. The asynchronous behaviour is not a problem for the code shown.

Upvotes: 0

schlingel
schlingel

Reputation: 8575

What would happen if 20 objects would be created and the ajaxcall function would be called? Nothing much. The ajax calls would run asynchronously. When they have finished they are queued so that they run on the main thread when the current running operation on the main thread finished.

So the callback functions run all synchronous in a queue next time there's time for it. Nothing bad can happen here.

I don't understand your question about the constructor. What would that change? If you use your Hello objects they have an instance variable. This is is enclosed in the callback closure . Creating a new function doesn't change the value in another callback function.

If you use the same IDs the content could flash when the text changes and you don't know which callback would be ran last but that's the worst thing that could happen.

Upvotes: 1

James Montagne
James Montagne

Reputation: 78670

There should be no issue. You're calling the function 20 distinct times with 20 different ids.

Conceptually though. I'm not seeing why this is part of your object. The function does not use anything at all from the object itself.

Upvotes: 1

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