How to return a list/set via callback function when execution completes?

Question

In the below code:`

    function extract_nouns_from_reviews (reviews,callback){

      reviews.forEach(function(review,index){

          wordpos.getNouns(review,function(result){

              result.forEach(function(noun,index){
                 noun_set.add(noun);
                 //callback(noun_set);
              });

          });

      });
      //callback(noun_set);
   }

How do I return the result - noun_set via the callback ? Or is there any better way to accomplish this task ?

Look into [promises](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) and `Promise.all`. — Felix Kling, Jan 27 '17 at 06:07
Possible duplicate of [How do I return the response from an asynchronous call?](http://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Andreas, Jan 27 '17 at 06:09

score 0 · Answer 1 · answered Jan 27 '17 at 06:11

You can try async library to solve the problem.

var async = require('async');

function extract_nouns_from_reviews (reviews,callback){
   async.each(reviews, function(review, cb){
     wordpos.getNouns(review, function(result){
       result.forEach(function(noun){
         noun_set.add(noun);
       });
       cb();
     });
   }, function(err){
     callback(noun_set);
   });  
}

How to return a list/set via callback function when execution completes?

1 Answers1