Callbacks

The App.Helpers.Callbacks.new helper generates a callback object similar to element event listeners. It supports methods like on and trigger.

Event Scopes

Periods within event types are treated as "scopes", and all parent scopes are triggered by a child.

For example, triggering the event update.field.name will trigger any events attached to update.field.name, update.field, or update.

Triggering the event update will not trigger children like update.field.name.

var callbacks = App.Helpers.Callbacks.new();

callbacks.on("update", function() {
  console.log("Update!");
});

callbacks.on("update.field", function(name) {
  console.log("Field Update: " + name);
});

// Outputs: "Update!"
callbacks.trigger("update");

// Outputs: "Update!" and "Field Update: Test"
callbacks.trigger("update.field", "Test");

App.Helpers.Callbacks.new(object = null)

Generate a Callback object with App.Helpers.Callbacks.new().

If the optional object argument is given, the callback method will be bound to the object when triggered, and you can use this to refer to object inside the method.

on(type, method)

Runs the method callback when type is triggered.

var callbacks = App.Helpers.Callbacks.new();
callbacks.on("type", function() {
  console.log("Triggered!");
});

trigger(type, parameters...)

Runs any callbacks attached to the type value, passing the parameters given.

var callbacks = App.Helpers.Callbacks.new();
callbacks.on("type", function(one, two) {
  console.log("One: " + one);
  console.log("Two: " + two);
});

// Outputs "One: 1" and "Two: 2"
callbacks.trigger("type", 1, 2);

trigger_synchronous(type, parameters...)

Runs any callbacks attached to the type value, waiting for any Promise values returned by a callback to resolve before running the next callback. If a returned Promise rejects, subsequent callbacks will not run.

This method is used to manage submission validation methods, like validate, before_save, and after_save, which run synchronously and only trigger if the previous method's callbacks all resolved. The usage is similar to the example below:

submission.callbacks = App.Helpers.Callbacks.new(submission);

submission.callbacks.trigger_synchronous("validate").then(function() {
    submission.callbacks.trigger_synchronous("before_save").then(function() {
        submission.save().then(function() {
          submission.callbacks.trigger_synchronous("after_save");
        });
    });
});