Creating custom events in a JavaScript constructor function

Question

Creating custom events in a JavaScript constructor function

Just beginning to learn JavaScript. I have a custom function that I want to assign events to in the constructor.

var myFunction = function(){
/*
some code
*/

}
myFunction.prototype.add=function(){

/*
adding item*/

}

Now I am looking to add an event to the constructor

var newFunction = new myFunction;

myFunction.onadd(function(){
/*execute on adding item*/
});

I will need to attach it with various functions multiple times.

What is the best way to add events and call the functions?

javascript jquery oop prototype

Answer 1

Answer №1

In this explanation, the concept is divided into two main parts. The first part, labeled as on, is responsible for gathering handlers and event triggers. Specifically, in your scenario, the event trigger is identified as add.

Within the on function, the handlers are organized based on the assigned event:

function yourConstructor(){
  this.events = {};
}

yourConstructor.prototype.on = function(eventName, handler){
  // A new property named `eventName` is created within `this.events`,
  // While an array stores all associated handlers for that particular `eventName`.
}

The second part involves executing specific handlers tied to a function, such as add:

yourConstructor.prototype.add = function(){
  // Perform the desired operations of the add function
  // Subsequently, execute all handlers stored in the `this.events.add` array.
}

Answer 2

In this explanation, the concept is divided into two main parts. The first part, labeled as on, is responsible for gathering handlers and event triggers. Specifically, in your scenario, the event trigger is identified as add.

Within the on function, the handlers are organized based on the assigned event:

function yourConstructor(){
  this.events = {};
}

yourConstructor.prototype.on = function(eventName, handler){
  // A new property named `eventName` is created within `this.events`,
  // While an array stores all associated handlers for that particular `eventName`.
}

The second part involves executing specific handlers tied to a function, such as add:

yourConstructor.prototype.add = function(){
  // Perform the desired operations of the add function
  // Subsequently, execute all handlers stored in the `this.events.add` array.
}

Answer 3

Answer №2

Creating your own eventing system is an option, but I would recommend utilizing existing libraries that are already available. Here are a few good options:

If you're interested in seeing how microevent works, check out this jsFiddle example.

function Person(name) {
    this.name = name;
}

Person.prototype.sayName = function () {
    alert('My name is ' + this.name);
    this.trigger('nameSaid');  //trigger the nameSaid event
};

//Apply the MicroEvent mixin to make Person instances observable
MicroEvent.mixin(Person);

//Create a new Person instance
var o = new Person('John Doe');

//Listen for the nameSaid event
o.bind('nameSaid', function () {
    alert(this.name + ' just said its name!');
});

o.sayName();

Answer 4

Creating your own eventing system is an option, but I would recommend utilizing existing libraries that are already available. Here are a few good options:

If you're interested in seeing how microevent works, check out this jsFiddle example.

function Person(name) {
    this.name = name;
}

Person.prototype.sayName = function () {
    alert('My name is ' + this.name);
    this.trigger('nameSaid');  //trigger the nameSaid event
};

//Apply the MicroEvent mixin to make Person instances observable
MicroEvent.mixin(Person);

//Create a new Person instance
var o = new Person('John Doe');

//Listen for the nameSaid event
o.bind('nameSaid', function () {
    alert(this.name + ' just said its name!');
});

o.sayName();

Creating custom events in a JavaScript constructor function

Answer №1

Answer №2

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