[javascript] how to break the _.each function in underscore.js

I'm looking for a way to stop iterations of underscore.js _.each() method, but can't find the solution. jQuery .each() can break if you do return false.

Is there a way to stop underscore each()?

_([1,2,3]).each(function(v){
    if (v==2) return /*what?*/;
})

Update:

_.find would be better as it breaks out of the loop when the element is found:

var searchArr = [{id:1,text:"foo"},{id:2,text:"bar"}];
var count = 0;
var filteredEl = _.find(searchArr,function(arrEl){ 
              count = count +1;
              if(arrEl.id === 1 ){
                  return arrEl;
              }
            });

console.log(filteredEl);
//since we are searching the first element in the array, the count will be one
console.log(count);
//output: filteredEl : {id:1,text:"foo"} , count: 1

** Old **

If you want to conditionally break out of a loop, use _.filter api instead of _.each. Here is a code snippet

var searchArr = [{id:1,text:"foo"},{id:2,text:"bar"}];
var filteredEl = _.filter(searchArr,function(arrEl){ 
                  if(arrEl.id === 1 ){
                      return arrEl;
                  }
                });
console.log(filteredEl);
//output: {id:1,text:"foo"}

You can have a look to _.some instead of _.each. _.some stops traversing the list once a predicate is true. Result(s) can be stored in an external variable.

_.some([1, 2, 3], function(v) {
    if (v == 2) return true;
})

See http://underscorejs.org/#some

Like the other answers, it's impossible. Here is the comment about breaker in underscore underscore issue #21

worked in my case

var arr2 = _.filter(arr, function(item){
    if ( item == 3 ) return item;
});

_([1,2,3]).find(function(v){
    return v if (v==2);
})

You cannot break a forEach in underscore, as it emulates EcmaScript 5 native behaviour.

I believe if your array was actually an object you could return using an empty object.

_.({1,2,3,4,5}).each(function(v){  
  if(v===3) return {}; 
});

Maybe you want Underscore's any() or find(), which will stop processing when a condition is met.

Update:

You can actually "break" by throwing an error inside and catching it outside: something like this:

try{
  _([1,2,3]).each(function(v){
    if (v==2) throw new Error('break');
  });
}catch(e){
  if(e.message === 'break'){
    //break successful
  }
}

This obviously has some implications regarding any other exceptions that your code trigger in the loop, so use with caution!

It's also good to note that an each loop cannot be broken out of — to break, use _.find instead.

http://underscorejs.org/#each