How do I return the response from an asynchronous call?

vegan_vicky

How do I return the response/result from a function foo that makes an asynchronous request? I am trying to return the value from the callback, as well as assigning the result to a local variable inside the function and returning that one, but none of those ways actually return the response — they all return undefined or whatever the initial value of the variable result is. Example of an asynchronous function that accepts a callback (using...

Originally asked by Felix Kling on Stack Exchange (stackoverflow) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

→ For a more general explanation of asynchronous behaviour with different examples, see Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference → If you already understand the problem, skip to the possible solutions below. The problem The A in Ajax stands for asynchronous . That means sending the request (or rather receiving the response) is taken out of the normal execution flow. In your example, $.ajax returns immediately and the next statement, return result; , is executed before the function you passed as success callback was even called. Here is an analogy which hopefully makes the difference between synchronous and asynchronous flow clearer:...

Full answer by Felix Kling: https://stackoverflow.stackexchange.com/a/14220323 (CC BY-SA 4.0).

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