JS Function with an Array of Callbacks

Question

I am trying to figure out how the best way to go about creating a function with multiple callbacks.

In short, I have different triggers throughout an application that can send out emails when key actions are taken (such as when a ticket is closed or a member has been assigned to it). The tricky part is that multiple different, emails needs to go out at the same time on occasion.

Here is my email function:

function sendEmail(template, to, cc, bcc, callback, optional=null){

// Define vars needed
var body = '',
    subject = '';

// Based on the template..
switch(template){

    case 'updatedTask':

        // Define the subject
        subject = 'Tool Request - Updated Task';

        // Define our body
        body += 'Hello, <br /><br />';
        body += 'Blah Blah';
        body += 'Footer';

    break;
    case 'removedTaskOwner':

        // Define the subject
        subject = 'Tool Request - Removed Task Owner';

        // Define our body
        body += 'Hello, <br /><br />';
        body += 'Blah Blah';
        body += 'Footer';

    break;
    case 'completedTask':

        // Define the subject
        subject = 'Tool Request - Completed Task';

        // Define our body
        body += 'Hello, <br /><br />';
        body += 'Blah Blah';
        body += 'Footer';

    break;
}


// Send our email
$.ajax({
    url: "../resources/Classes/class.email.php",
    type: "POST",
    cache: false,
    data: {
        from: "[email protected]",
        to: to,
        cc: cc,
        bcc: bcc,
        subject: subject,
        body: body
    },
    error: function(err) {
        alert(err.statusText);
    },
    success: function(data) {
        // Handle Callback
        callFunction(callback);
    }
});
}

// Callbacks
function callFunction(func) {
    func();
}

// Reload the page
function refresh(){
    location.reload('true');
}

This is how I use the function currently:

 // Once the email is sent, it triggers a function called refresh
 sendEmail('taskUpdated', toArray, '', '', refresh, '');

This is what I am trying to do:

// Define our remove function as a callback
var remove = function() {
 sendEmail('removeTaskOwner', toArray, '', '', refresh, '');
}

// Define our completed function as a callback
var completed = function() {
  sendEmail('completedTask', toArray, '', '', refresh, '');
}

// If there is a completed date, we need to send out two separate emails
var callbacks = Array();
if(completionDate){
  callbacks.push('completed', 'remove');
}else{
  callbacks.push('remove');
}

sendEmail('taskUpdated', toArray, '', '', callbacks, '');

The issue I am running into is that it doesn't appear callbacks can be an array of callback functions.

The overall needed feature of what I am trying to do is the ability to pass multiple templates & recipients and have a final function be triggered at the end of the emails being sent out, such as the page refreshing.

callback can be an array, but you must treat it as such. You're attempting to invoke the array as a function. — Kenney
– Kenney, Commented Nov 19, 2015 at 16:48

Halcyon · Accepted Answer · 2015-11-19 16:48:17Z

1

You can use Promises. jQuery has this built-in already. $.ajax returns a promise.

function sendEmail(template, to, cc, bcc, optional=null){

    // etc..

    // return here!
    return $.ajax({
        url: "../resources/Classes/class.email.php",
        type: "POST",
        cache: false,
        data: {/*etc*/}
    });
}

Then you can do:

var remove = function() {
    sendEmail('removeTaskOwner', toArray, '', '', '' ).done(refresh);
}

// Define our completed function as a callback
var completed = function() {
    sendEmail('completedTask', toArray, '', '', '').done(refresh);
}

sendEmail("taskUpdated", toArray, "" , "").done(function () {
    if(completionDate){
        completed();
    }
    remove();
}).fail(function (err) {
    alert(err.statusText);
});

answered Nov 19, 2015 at 16:48

Halcyon

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2 Comments

SBB Over a year ago

This looks promising ;) - Let me implement it and I will let you know the outcome. I really appreciate the code examples.

SBB Over a year ago

Everything appears to be working with this. While I am receiving all of the emails, when I view the console in Firefox, I usually see one of the 3 AJAX calls to the email class turn red as if there may be some type of async issue and something is trying to reload before its complete? If that doesn't seem possible with your example, I will try and debug it a little further as I am still getting the emails as expected.

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