CODEWITHSUNDEEP
javascriptloopsasynchronouscallback
laggingreflex
laggingreflex

Reputation: 34627

Async callback loop

I want to make a loop as follows

asyncFunction(function(returnedVariable){
    if(returnedVariable < 10 )
        // call asyncFunction() again
    else
        // break/exit
});

Is this possible?

I can't call it from inside because then 

asyncFunction(function(returnedVariable){
    if(returnedVariable < 10 )
        asyncFunction(function(returnedVariable){
            // ???
        });
    else
        // break/exit
});

Upvotes: 1

Views: 94

Answers (1)

Plato
Plato

Reputation: 11052

EDIT - original answer at bottom. after rereading I think you can just do this for your case (although i've never tried referring to a function inside itself like this):

function asyncFunction(callback){ /* ... do stuff then callback() */ };

function myCallback(returnedVariable){
  if(returnedVariable < 10 ){
    asyncFunction(myCallback);
  } else {
    // break/exit
  }
}

asyncFunction(myCallback);

i'm sure there's a way to do it without a library but for simplicity I always just use caolan/async which works in both node and browser:

var async = require('async');
// for browser, above this script:
// <script src="/path/whatever/async.js" type="text/javascript"></script>

function wrapper(callback){
  var lastReturn = 0;

  function test(){ 
    return lastReturn < 10 
  };

  function iterate(next){
    lastReturn = doSomethingWithPrev(lastReturn);
    next();
  };

  function complete(err){
    if(err){ return callback(err) };
    callback(null, lastReturn);
  };

  async.whilst(test, iterate, complete);
};

Upvotes: 1

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