Run request until response is what was requested with $q

Question

I have this plunker to illustrate my problem:

http://plnkr.co/edit/tsBy2K0xv6bboBlZRM8c

$scope.start = function() {

  runThisUntil("Ok");
  //here I would like to do this:
  //runThisUntil("Ok").then(function () {
  //doSomeStuff()  
  //});

}

$scope.clear = function() {
  $scope.responses = [];
}

function runThisUntil(criteria) {

  runThis(criteria);



}

function runThis(criteria) {
  run().then(function (response) {
    if (response == criteria) {
      $scope.responses.push("Done");
    } else {
      $scope.responses.push("Wait");
      runThisUntil(criteria);
    }
  });
}


var okWhen = 10;
var start = 0;
function run() {

  var deferred = $q.defer();
  $timeout(function () {
    if (start !== okWhen) {
    start += 1;
    deferred.resolve("Bad");
  } else {
    deferred.resolve("Ok")
    start = 0;
  }
  }, 100);


  return deferred.promise;


}
}

What I'm trying to simulate here is form of loop where I do requests to an http server that does work in batches and respondes with "There is still more work" until "Work is done".

When I tried to do this with promises I ended up creating new deferred promises with $q so the initial promise I was waiting for to be resolved never got resolved because the request was repeated which I do by executing the same function that I am in again if it's not done.

--Edit I figured I could do this with a $scope.$broadcast() when it's done, but I would like to solve this by using $q if possible and not listen to events if possible.

yeouuu · Accepted Answer · 2015-11-05T10:38:19.787

0

UPDATE:

var app = angular.module('myApp', []);

angular.module('myApp').controller('TestCtrl', ["$timeout", "$interval", "$scope", "$q", function TestCtrl($timeout, $interval, $scope, $q) {

  activate();

  $scope.responses = [];

  function activate() {

    $scope.start = function() {

      runThisUntil("Ok").then(function() {
        $scope.responses.push("Pushed final");;
      });
    }

    $scope.clear = function() {
      $scope.responses = [];
    }

    function runThisUntil(criteria) {

      return runThis(criteria);
    }

    function runThis(criteria) {
      return run().then(function (response) {
        $scope.responses.push("Done");
      }, function () {
        $scope.responses.push("Wait");
        return runThis(criteria);
      });
    }


    var okWhen = 10;
    var start = 0;
    function run() {

      var deferred = $q.defer();
      $timeout(function () {
        if (start !== okWhen) {
        start += 1;
        deferred.reject("Bad");
      } else {
        deferred.resolve("Ok")
        start = 0;
      }
      }, 100);

      return deferred.promise;
    }

  }


}]);

http://plnkr.co/edit/MYn6otWMmxHFDd41jBpI?p=preview

edited Nov 05 '15 at 10:38

answered Nov 05 '15 at 09:56

yeouuu

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can you illustrate with a working plunker? That cannot work as runThis does not return a promise – Ashkan Hovold Nov 05 '15 at 10:14
Excellent! Thanks, will need to understand this but yes it was exactly what I wanted :) – Ashkan Hovold Nov 05 '15 at 10:44
You need to look into the promises a bit. resolve() and reject() can do some great stuff. – yeouuu Nov 05 '15 at 10:49
How can I pass data to the final event? I wanted to do this: runThisUntil("Ok").then(function(response) { $scope.responses.push(response); }); but response was undefined – Ashkan Hovold Nov 05 '15 at 10:53
You need to return it in the then functions. – yeouuu Nov 05 '15 at 11:48
Please see http://stackoverflow.com/questions/23803743/what-is-the-explicit-promise-construction-antipattern-and-how-do-i-avoid-it – Benjamin Gruenbaum Nov 05 '15 at 13:36

Run request until response is what was requested with $q

1 Answers1