How to exit (escape) a function from for loop inside of it?

Question

This is theoretical question to understand how many escapes (return or exit) can apply to nested loops or other controls and functions.

I confused about this because I am stuck in the code How to escape from for ... each loop and method at the same time?

I can't stop iterating over options in select element.

I tried return and return false already, but am unsuccesful.

Generally how we can do that?

function() {
    for (...) {
        if (...) {
            $(...).each(function() {
               // You have to exit outer function from here
            });
        }
    }
}

possible duplicate of [Nested jQuery.each() - continue/break](http://stackoverflow.com/questions/3267508/nested-jquery-each-continue-break) — nalply, Mar 25 '13 at 13:08

score 10 · Accepted Answer · answered Mar 25 '13 at 12:53

10

Use a shared variable between the loops. Flip it to true at the end of the each() loop if you want to exit and at the end of the for-loop check for it being true. If yes, break out of it.

answered Mar 25 '13 at 12:53

Konstantin Dinev

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Yes @Konstantin D this will solve my problem. But shall we say there is no direct solution to this? – caglaror Mar 25 '13 at 13:04
2

@caglaror I would say yes. – Konstantin Dinev Mar 25 '13 at 13:04

score 4 · Answer 2 · edited May 23 '17 at 12:02

4

I would do it this way:

Create a boolean variable to check on each loop, and if the variable is true, then exit the loop (do this for each).

var exitLoop = false;

 $(sentences).each(function() {
    if(exitLoop) {return;}
    var s = this;
    alert(s);
    $(words).each(function(i) {
    if(exitLoop) {return;}
        if (s.indexOf(this) > -1)
        {
            alert('found ' + this);
            throw "Exit Error";
        }
    });
});

Note this is not the correct use of a try-catch as a try-catch should strictly be used for error handling, not jumping to different sections of your code - but it will work for what you're doing.

If return is not doing it for you, try using a try-catch

try{
$(sentences).each(function() {
    var s = this;
    alert(s);
    $(words).each(function(i) {
        if (s.indexOf(this) > -1)
        {
            alert('found ' + this);
            throw "Exit Error";
        }
    });
});
}
catch (e)
{
    alert(e)
}

Code taken from this answer

edited May 23 '17 at 12:02

Community

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1

answered Mar 25 '13 at 12:52

What have you tried

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This code works fine, there is no reason for a downvote. Care to explain? – What have you tried Mar 25 '13 at 13:01
1

A try catch should be used for error handling, not for jumping to different sections of a script. – What have you tried Mar 25 '13 at 13:08
@nalply I edited, not sure what you're looking for to be honest – What have you tried Mar 25 '13 at 13:10
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/26869/discussion-between-nalply-and-evan) – nalply Mar 25 '13 at 13:21

score 1 · Answer 3 · answered Nov 10 '17 at 12:29

1

The loop can also be exited by changing the iterator value.

var arr = [1,2,3,4,5,6,7,8,9,10];

for(var i = 0;i<arr.length;i++){

  console.log(i);
  compute(i);

  function compute(num){
    //break is illegal here
    //return ends only compute function
    if(num>=3) i=arr.length;
  }

}

answered Nov 10 '17 at 12:29

Paweł

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But the nested loops? Inner loops will continue to iterate. – caglaror Nov 16 '17 at 08:13

score 0 · Answer 4 · answered May 21 '21 at 05:09

0

"label"s are the solution for scope processes like breaking loops. Here is the built-in answer I realized after years: https://css-tricks.com/you-can-label-a-javascript-if-statement/

answered May 21 '21 at 05:09

caglaror

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score 0 · Answer 5 · answered Jun 01 '22 at 23:20

Not ideal but you can do

let result = false;
function() {
    for (...) {
        if (...) {
            $(...).each(function() {
                result = true;
               
            });
        }
    }
    if (result == true){
        return;
    }

}

score -1 · Answer 6 · answered Mar 25 '13 at 12:51

-1

As in most languages. The keyword to exit a loop is break; More info here: http://www.w3schools.com/js/js_break.asp

answered Mar 25 '13 at 12:51

Toon Casteele

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Just wondering to the down voter? What is incorrect about my answer? – Toon Casteele Mar 25 '13 at 12:54
if the point of i wrote comment we `break;` the code it said break is Illegal at there. – caglaror Mar 25 '13 at 12:55
I don't know if you realize, but `for each()` is not javascript code. At least not that I know of – Toon Casteele Mar 25 '13 at 13:04
I've said this before. Not everything on wc3schools.com is wrong. And if the link I posted contains correct information, please shut it. – Toon Casteele Mar 26 '13 at 07:09

How to exit (escape) a function from for loop inside of it?

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