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
            });
        }
    }
}

Solution 1

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.

Solution 2

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

Solution 3

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;
  }

}

Comments

[Toon Casteele]

Just wondering to the down voter? What is incorrect about my answer?

[caglaror]

if the point of i wrote comment we break; the code it said break is Illegal at there.

[What have you tried]

This code works fine, there is no reason for a downvote. Care to explain?

[caglaror]

Yes @Konstantin D this will solve my problem. But shall we say there is no direct solution to this?

[Konstantin Dinev]

@caglaror I would say yes.

[Toon Casteele]

I don't know if you realize, but for each() is not javascript code. At least not that I know of

[What have you tried]

A try catch should be used for error handling, not for jumping to different sections of a script.

[What have you tried]

@nalply I edited, not sure what you're looking for to be honest

[nalply]

let us continue this discussion in chat

[Toon Casteele]

I've said this before. Not everything on wc3schools.com is wrong. And if the link I posted contains correct information, please shut it.

[caglaror]

But the nested loops? Inner loops will continue to iterate.