Custom solution to implement callback function

Question

Is it possible to wrap functions like setTimeout and then fire callback. Like in jQuery $(selector).on('action', callback).

var obj = {
   mth1: function (callback) {
       //----need to wrap to something
          setTimeout(function () { console.log("1"); }, 1000);
          console.log('2');
       //----
       // callback;
   }
};
function callback() {
   console.log('3');
};
(function () { obj.mth1(callback); }) ();

What I need:

2
1
3

Is there any reason you can't simply run callback() after console.log(1) in the setTimeout function? — Rory McCrossan
– Rory McCrossan, Commented Feb 28, 2012 at 14:24
That is specific case, below i wrote another situations, i can repost: But imagine that will be another code instead of setTimeout, which will return pdf or error message (if fail on generating pdf). So i need to wait while response will come back and if response is OK - than call downloading dialog, else if response return 500 - show error message in label. I can`t figure it out how to call downloading dialog if pdf returned from ajax. — WISEMAN
– WISEMAN, Commented Feb 29, 2012 at 12:14

mkilmanas · Accepted Answer · 2012-02-28 14:26:18Z

2

Simply add it at the end of your function inside the setTimout

// *snip*
setTimeout(function () { 
    console.log("1");
    callback();
}, 1000);
// *snip*

answered Feb 28, 2012 at 14:26

mkilmanas

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1 Comment

WISEMAN Over a year ago

But imagine that will be another code instead of setTimeout, which will return pdf or error message (if fail on generating pdf). So i need to wait while response will come back and if response is OK - than call downloading dialog, else if response return 500 - show error message in label. I can`t figure it out how to call downloading dialog if pdf returned from ajax

Didier Ghys · Accepted Answer · 2012-02-29 10:24:26Z

0

Not sure what you're asking for. Just make sure it is a function and call it:

mth1: function (callback) {

   //----need to wrap to something
   setTimeout(function () { 
      console.log("1");
      // be sure it is a function
      if (callback&& getType.toString.call(callback) == '[object Function]';) {
        // call it
        callback();
      }
   }, 1000);

   console.log('2');

}

edited Feb 29, 2012 at 10:24

answered Feb 28, 2012 at 14:26

Didier Ghys

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2 Comments

WISEMAN Over a year ago

Still have the same result: 2;3;1

Didier Ghys Over a year ago

sorry i did not see the part "What I need: 2, 1, 3". You can make the call to the callback inside the function of the setTimeout. Juts make sure, as my answer shows, to check "callback" is executable function so your code does not break if an invalid callback is passed as a parameter.

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