Wait for callback before continue for loop

Question

I've a for-loop I'm looping through.

I want to make a custom modal and wait for a response before continue it.

How can I achieve this? I know I've to wait for a callback.

Like this example:

 for(var x in array){             alert(x);             console.log(x);         } 

It does exactly what I want to. But I want to have three buttons. But alert is not part of javascript(? It's in the browser.)

So, do you guys have an idea?

I was thinking about doing something like this:

var run = true; function foo(){     if (run){         setTimeout(foo, 500);     } }  function stop(){     run = false; }  foo(); 

and then wait for a stop which calls on a button click before continue. But is this really good practice?

Or use a lambda function as a parameter to the customAlert and a "global" variable that holds the current position of the array I'm going through and do this with functions. Like: Check if array is still holding keys greater than X. Then do the function again and each time increase the global X.

Thank you lostsource for the code: Oh, I got an idea; I'll simply use lostsource's solution inside an anonymous function, so I don't get global variables. Excellent.

(function(){  })(); 

Answer 1

Assuming this is your array

var list = ['one','two','three']; 

You can try using this loop / callback approach

var x = 0; var loopArray = function(arr) {     customAlert(arr[x],function(){         // set x to next item         x++;          // any more items in array? continue loop         if(x < arr.length) {             loopArray(arr);            }     });  }  function customAlert(msg,callback) {     // code to show your custom alert     // in this case its just a console log     console.log(msg);      // do callback when ready     callback(); } 

Usage:

// start 'loop' loopArray(list); 

JSFiddle here: http://jsfiddle.net/D9AXp/

Answer 2

MaggiQall, I know you have an answer but I have a flexible solution that may be of interest to you or maybe to someone else.

The solution depends on jQuery (1.7+) and jQuery UI's dialog, but is implemented as a custom method of the Array prototype, not as a jQuery plugin.

Here's the Array method :

Array.prototype.runDialogSequence = function(dialogCallback, startIndex, endIndex){     startIndex = Math.max(0, startIndex || 0);     endIndex = Math.min(this.length - 1, endIndex || this.length - 1);     var sequenceIndex = 0,         arr = this,         dfrd = $.Deferred().resolve(startIndex);     function makeCloseFn(seqData){         return function(event, ui){             if(seqData.continue_) { seqData.dfrd.resolve(seqData.arrayIndex+1, seqData); } //continue dialog sequence             else { seqData.dfrd.reject(seqData.arrayIndex, seqData); } //break dialog sequence         }     }     $.each(this, function(i){         if(i < startIndex || i > endIndex) { return true; }//continue         dfrd = dfrd.then(function(arrayIndex){             var seqData = {                 dfrd: $.Deferred(),                 arrayIndex: arrayIndex,                 sequenceIndex: ++sequenceIndex,                 length: 1 + endIndex - startIndex,                 item: arr[arrayIndex],                 continue_: false             };             dialogCallback(seqData).on("dialogclose", makeCloseFn(seqData));             return seqData.dfrd.promise();         });     });     return dfrd.promise(); } 

Array.runDialogSequence() relies on :

• A dialog template in the document's body, fit to be populated with text/values.
• an array of similar items (typically javascript objects) containing the data required to populate the dialog, in sequence.
• passing, as the first argument, a correctly constructed "openDialog" function.

Here's a sample "openDialog" function with explanatory comments :

function openDialog(seqData){     /*     seqData is an object with the following properties:         dfrd: A Deferred object associated with the current dialog. Normally resolved by Array.runDialogSequence() to run through the sequence or rejected to break it, but can be resolved/rejected here to force the dialog sequence to continue/break. If resolved, then pass (seqData.arrayIndex+1, seqData), or custom values. If rejected, typically pass (seqData.arrayIndex, seqData).         arrayIndex: The current array index.         sequenceIndex: The current index within the sequence. Normally the same as arrayIndex but Differs when a non-zero startIndex is specified.         length: The full length of the dialog sequence.         item: The current item from the array.         continue_: (false) Set to true to allow the sequence to continue.     */     var item = seqData.item;     var $d = $("#d");     $d.dialog({         title: 'Dialog (' + seqData.sequenceIndex + ' of ' + seqData.length + ')',         modal: true,         buttons: {             "Continue": function(){                 seqData.continue_ = true;//set to true before closing to go to next dialog.                 $(this).dialog("close");             },             "Cancel": function(){                 $(this).dialog('close');//closing with seqData.continue_ set to its default value false will break the dialog sequence.             }         }     }).find("#message").text(item);//Typically you will do a lot more here to populate the dialog with item data.     return $d;//openDialog() must return a dialog container, jQuery-wrapped. } 

Array.runDialogSequence() returns a jQuery promise, allowing custom actions to be performed when the dialog sequence completes (done function) or is broken in mid-sequence (fail function).

Here are a couple of sample calls :

//Simplest possible $("#myButton1").click(function(){     myArray.runDialogSequence(openDialog); });  //Call with custom startIndex and endIndex, and chanined `.then()` to provide custom actions on break/completion. $("#myButton2").click(function(){     myArray.runDialogSequence(openDialog, 1, 3).then(function(i, seqData){         alert('All dialogs complete - last item = "' + seqData.item + '"');     }, function(i, seqData){         alert('Dialog sequence was broken at item ' + i + ' "' + seqData.item + '"');     }); }); 

DEMO

This is as close to a generalized solution as my imagination allows.