$.each wait for promise from each object

Question

I have another callback/promise issues :-)

I'm trying to implement a series of function each of the function are waiting for a return value from the next one.

I have an ajax call that returns a json on success, in the success block i'm sending this json to an async function validation.

In validation() I'm loading a script and for each object I sending it to availability function, i want to wait for the availability to complete and to return value, each value that is return is being pushed to an array that i want to send it in the end.

I'm having trouble with the callback implementations.

var validArr = [];

function checkStory(callback) {
  $.ajax({
    url: "",
    type: "GET",
    data: "",
    async: true,
    headers: {
      Accept: "application/json"
    },
    success: function(data) {
      if (data.isDoc == true) {
        _checkDoc(callback);
      } else {
        if (data.responseObj) {
          validation(data.responseObj);
        } else {
          callback(data.count);
        }
      }
    },
    error: function(err) {
      console.log("No books");
    }
  });
}

function validation(responseObj) {
  getScript('books.js',
    function() {
      $.each(responseObj, function(_index, _value) {
        var res = aviliabilty(_value);
        if (res) {
          validArr.push(_index, true);
        } else {
          validArr.push(_index, false);
        }
      });
      //return after all objects completed execution 

      return validArr;
    }
  );
}

function aviliabilty(entry) {
  DM.ct.get(entry, function(response) {
    if (response) {
      for (var idx = 0, adLen = response.ds.length; idx < adLen; idx++) {
        var bk = response.ds[idx];
        for (var creaIdx = 0, crea = bk.creatives.length; creaIdx < crea; creaIdx++) {
          var creative = bk.creatives[creaIdx];
          if (creative.type == "line") {
            for (var mfIdx = 0, mfLen = creative.Files.length; mfIdx < mfLen; mfIdx++) {
              var mediaFile = creative.Files[mfIdx];
              if (mediaFile.type == "horror") {
                return true;
              }
            }
          } else if (creative.type != "horror") {
            return false;
          }
        }

      }
    }

  });
}


// a function to get the script asynchronously
function getScript(url, success) {
    var script = document.createElement('script');
    script.src = url;
    var head = document.getElementsByTagName('head')[0],
        done = false;
    // Attach handlers for all browsers
    script.onload = script.onreadystatechange = function() {
        if (!done && (!this.readyState || this.readyState == 'loaded' || this.readyState == 'complete')) {
            done = true;
            success();
            script.onload = script.onreadystatechange = null;
            head.removeChild(script);
        }
    };
    head.appendChild(script);
}

What is `getScript()` and why do you call it every time `validation()` is called? What is `_checkDoc()`? Who calls `checkStory()`? — Tomalak, Mar 30 '16 at 13:45
@Tomalak, _checkDoc() and checkStory() are other function in my current script and not being used in my flow. validation is not being called every time, in validation i'm executing aviliabilty() for each object in my response. DM.ct is a function from external script. — ohadsas, Mar 30 '16 at 14:14

ShacharW · Answer 1 · 2016-03-30T13:51:43.150

Option 1: use a callback -

    validation(data.responseObj, function(){

    })

    function validation(responseObj, callback) {

       //your code....

       callback(validArr)    
    }

Option 2: Use Promises -

validation(data.responseObj).then(function(validArr){
});

function validation(responseObj, callback) {
```
   var defer = Q.defer()
   //your code....

   defer.resolve(validArr)

   return defer.promise
```
}

$.each wait for promise from each object

1 Answers1