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Nick Coffey
1,657 Pointsreturn vs callback? [Javascript]
Whats the difference between return and call back? Both gets back the same result in the example below. Since I saw callback in the javascript asynchronous course material, should I use callback when asynchronous functions are used?
function add(a, b, callback) {
callback(a + b);
}
add(2, 4, function(sum) {
console.log(sum); // 6
});
Return example:
function add(a, b, return) {
return(a + b);
}
add(2, 4, function(sum) {
console.log(sum); // 6
});
3 Answers
Nick Coffey
1,657 PointsAlright, one can store it in memory for later execution?
Jess W
9,490 PointsThis might help clear things up a little: https://developer.mozilla.org/en-US/docs/Glossary/Callback_function
This article is good too: https://dmitripavlutin.com/javascript-callback/#:~:text=The%20synchronous%20callback%20is%20executed,()%20and%20greet()%20functions.
I was only thinking of async callbacks when I answered your question, oops!
Nick Coffey
1,657 PointsThe asynchronous callback is executed after the execution of the higher-order function. -source: dmitripavlutin
I think that might be right. by higher order function, I think he means parent functions. Which would make sense.
Jess W
9,490 PointsRight, he means the higher order function is the function that has the callback as an argument. I hope this was helpful. I sure learned some things :)
Nick Coffey
1,657 PointsI realised that there is allot more: https://teamtreehouse.com/library/callback-functions-in-javascript
The callback function does not seem to be apart of of the JS fullstack track for some reason. Or maybe I'm bad at finding it.
Jess W
9,490 PointsWow, there is a lot to callbacks if it has its own course! You're right, I don't think it's in the Full Stack track. I think you can get a lot done with just a basic understanding of callbacks, but I'll have to take this course too when I get a chance.
Jess W
9,490 PointsJess W
9,490 PointsA callback is a function that you want to run some time later, like when a specific event happens. For example, if you wanted to run a function
foo()when a button is pressed, you passfooas a callback like this:addEventListener("click", foo);That sets things up so thatfoowill automatically be called when your button is clicked.Use
returnwhen you want a function to immediately return a result.Does that help?