Related
I am creating a mini-library, sort of trying to reconstruct, at least partly, the way jQuery works for learning purposes and to understand better how object-oriented programming works.
I have recreated the jQuery methods click and addClass, but when I call them like:
$(".class1").click(function() {
$(".class1").addClass("class2"); // Works, but it adds class2 to all elements
this.addClass("class2"); // Doesn't work
});
I get an Uncaught Error saying this.addClass is not a function, which is normal, since I shouldn't be able to access another object's methods.
How is $(this) made in jQuery to mean the DOM element that triggered an event, so that in my case I can use it to add class2 only to the element clicked and not all elements that have the class class1?
P.S: I tried reading the jQuery file, but I feel like these waters are currently too deep for me.
Edit:
I always appreciate all the answers and the help I get on Stack Overflow, but telling me to use $(this) instead of this doesn't solve my issue, because $(this) doesn't exist in my code. I'm trying to learn how to create something like jQuery's $(this) & what's the logic behind it.
The click method is defined as follows:
$.prototype.click = function(callback) {
for (var i = 0; i < this.length; i++) {
this[i].onclick = function(event) {
callback.call(this, event);
}
}
};
With an extra 1.5 years of experience, this question becomes rather easy.
Alter $, so that, except string selectors, it can accept HTML elements.
Create a new instance of the object containing the HTML element given.
Call addClass with that as the context.
Code:
;(function() {
/* The object constructor. */
function ElementList(arg) {
/* Cache the context. */
var that = this;
/* Save the length of the object. */
this.length = 0;
/* Check whether the argument is a string. */
if (typeof arg == "string") {
/* Fetch the elements matching the selector and inject them in 'this'. */
[].forEach.call(document.querySelectorAll(arg), function(element, index) {
that[index] = element;
that.length++;
});
}
/* Check whether the argument is an HTML element and inject it into 'this'. */
else if (arg instanceof Element) {
this[0] = arg;
this.length = 1;
}
}
/* The 'click' method of the prototype. */
ElementList.prototype.click = function(callback) {
/* Iterate over every element and set the 'click' event. */
[].forEach.call(this, function(element) {
element.addEventListener("click", function(event) {
callback.call(this, event);
});
});
}
/* The 'addClass' method of the prototype. */
ElementList.prototype.addClass = function(className) {
/* Iterate over every element. */
[].forEach.call(this, function(element) {
/* Cache the classList of the element. */
var list = element.classList;
/* Add the specified className, if it doesn't already exist. */
if (!list.contains(className)) list.add(className);
});
}
/* The global callable. */
window.$ = function(arg) {
return new ElementList(arg);
}
})();
/* Example */
$("#b1").click(function() {
$(this).addClass("clicked");
console.log(this);
});
<button id="b1">Click</button>
You need to use call, apply, bind or some combination of those to set the callback's context to the DOM Node. Here is a contrived example of jquery's each method that sets the context of the callback using call:
var $ = {
each: function(selector, callback) {
var collection = Array.from(document.querySelectorAll(selector));
collection.forEach(function(element, index) {
// the magic...
callback.call(element, index, element);
});
}
}
$.each('.foo', function(idx, el) {
console.log(this.textContent);
});
this is the native JavaScript element and only exposes the native API. You need to pass it to the jQuery constructor in order to access jQuery's API
$(this).addClass("class2"); // This will work
One possible way (only selectors are accepted):
$ = function(selector) {
this.elements = '';//Select the element(s) based on your selector
this.addClass = function(klass) {
//apply your klass to you element(s)
return this;
};
this.click= function(handler) {
//Attach click event to your element(s)
return this;
};
return this;
};
Please keep in mind it's just an example.
Edit 1:
In your click method you are calling the handler in the wrong scope (the anonymous function scope). You need to use the outer scope:
$.prototype = {
click: function(callback) {
console.log(this.length);
var _self = this;
for (var i = 0; i < this.length; i++) {
this[i].onclick = function(event) {
//this here presents the anonymous function scope
//You need to call the handler in the outer scope
callback.call(_self, event);
//If you want to call the handler in the Element scope:
//callback.call(_self[i], event);
}
}
}
}
Note: In your example, this.addClass("class2"); doesn't work because jQuery calls the click handler in the Element scope not jQuery scope. Therefore, this presents the Element which dosen't have the addClass method;
Ok, I understand now your question. Let me try to help you again.
jQuery doesn't knows what DOM element do you use when you give it to selector. It doesn't parsing it or something else. Just save it to the internal property.
Very simplified code to understand:
$ = function(e) {
// finding object. For example "this" is object
if (typeof e !== 'object' || typeof e.className === 'undefined') {
if (typeof e == 'string') {
if (e[0] == '#') {
e = document.getElementById(e.substring(1));
} else if (e[0] == '.') {
e = document.getElementsByClassName(e.substring(1))[0];
} else {
// ... etc
}
}
// ... etc
}
var manager = {
elem: e,
addClass: function(newClass) {
manager.elem.className = manager.elem.className + ' ' + newClass;
return manager;
},
click: function(callback) {
// here is just simple way without queues
manager.elem.onclick = function(event) {
callback.call(manager, event);
}
}
}
return manager;
}
I'm trying to implement a little MVC framework and now I'm implementing the view-model binder, I mean, when the model changes, trigger a refresh/render/whatever on the model. So, I need an event listener on a object:
model.on("customEvent",appendItem);
$("#button").on("click",function(){
model.add(item);
model.trigger("customEvent");
});
function appendItem(item) {
$("#content").append(item.toHTML());
}
So how can I create my event listener on objects?
If you are already using jQuery, you can use its built-in event handling facilities.
It's a little known fact that you can also put any kind of Javascript objects into a jQuery collection, not just DOM elements. Then you can use a limited set of jQuery methods (.data(), .prop(), .on(), .off(), .trigger() and .triggerHandler()) on these objects.
//create the model - it can be any kind of object
var model = {};
//pass it to the jQuery function and you have a jQuery collection
//you can put an event handler on the object
$(model).on('customEvent', function () { console.log('hehe'); });
//and trigger it
$(model).trigger('customEvent');
Read more in the Manual
Try the Demo
For those who are not using jQuery and are interested in wiring their own stuf, here's how you may achieve similar aim:
/**
* EventfulObject constructor/base.
* #type EventfulObject_L7.EventfulObjectConstructor|Function
*/
var EventfulObject = function() {
/**
* Map from event name to a list of subscribers.
* #type Object
*/
var event = {};
/**
* List of all instances of the EventfulObject type.
* #type Array
*/
var instances = [];
/**
* #returns {EventfulObject_L1.EventfulObjectConstructor} An `EventfulObject`.
*/
var EventfulObjectConstructor = function() {
instances.push(this);
};
EventfulObjectConstructor.prototype = {
/**
* Broadcasts an event of the given name.
* All instances that wish to receive a broadcast must implement the `receiveBroadcast` method, the event that is being broadcast will be passed to the implementation.
* #param {String} name Event name.
* #returns {undefined}
*/
broadcast: function(name) {
instances.forEach(function(instance) {
(instance.hasOwnProperty("receiveBroadcast") && typeof instance["receiveBroadcast"] === "function") &&
instance["receiveBroadcast"](name);
});
},
/**
* Emits an event of the given name only to instances that are subscribed to it.
* #param {String} name Event name.
* #returns {undefined}
*/
emit: function(name) {
event.hasOwnProperty(name) && event[name].forEach(function(subscription) {
subscription.process.call(subscription.context);
});
},
/**
* Registers the given action as a listener to the named event.
* This method will first create an event identified by the given name if one does not exist already.
* #param {String} name Event name.
* #param {Function} action Listener.
* #returns {Function} A deregistration function for this listener.
*/
on: function(name, action) {
event.hasOwnProperty(name) || (event[name] = []);
event[name].push({
context: this,
process: action
});
var subscriptionIndex = event[name].length - 1;
return function() {
event[name].splice(subscriptionIndex, 1);
};
}
};
return EventfulObjectConstructor;
}();
var Model = function(id) {
EventfulObject.call(this);
this.id = id;
this.receiveBroadcast = function(name) {
console.log("I smell another " + name + "; and I'm model " + this.id);
};
};
Model.prototype = Object.create(EventfulObject.prototype);
Model.prototype.constructor = Model;
// ---------- TEST AND USAGE (hopefully it's clear enough...)
// ---------- note: I'm not testing event deregistration.
var ob1 = new EventfulObject();
ob1.on("crap", function() {
console.log("Speaking about craps on a broadcast? - Count me out!");
});
var model1 = new Model(1);
var model2 = new Model(2);
model2.on("bust", function() {
console.log("I'm model2 and I'm busting!");
});
var ob2 = new EventfulObject();
ob2.on("bust", function() {
console.log("I'm ob2 - busted!!!");
});
ob2.receiveBroadcast = function() {
console.log("If it zips, I'll catch it. - That's me ob2.");
};
console.log("start:BROADCAST\n---------------");
model1.broadcast("crap");
console.log("end :BROADCAST\n---------------\n-\n-\n");
console.log("start:EMIT\n---------------");
ob1.emit("bust");
console.log("end:EMIT\n---------------");
<h1>THE CODE IS IN THE JavaScript SECTION!</h1>
<h3>AND... THE SHOW IS ON YOUR CONSOLE!</h3>
I've just started with Rivets.js, which looks promising as simple data-binding framework.
I've arrived at the point that I don't know how to pass "custom arguments" to the rv-on-click binder, so I tried to take the idea from this: https://github.com/mikeric/rivets/pull/34
My code:
rivets.binders["on-click-args"] = {
bind: function(el) {
model = this.model;
keypath = this.keypath;
if(model && keypath)
{
var args = keypath.split(' ');
var modelFunction = args.shift();
args.splice(0, 0, model);
var fn = model[modelFunction];
if(typeof(fn) == "function")
{
this.callback = function(e) {
//copy by value
var params = args.slice();
params.splice(0, 0, e);
fn.apply(model, params);
}
$(el).on('click', this.callback);
}
}
},
unbind: function(el) {
$(el).off('click', this.callback);
},
routine: function(el, value) {
}
}
This code is working, my question is: is this the correct way?
If you want to pass a custom argument to the event handler then this code might be simpler:
rivets.configure({
// extracted from: https://github.com/mikeric/rivets/issues/258#issuecomment-52489864
// This configuration allows for on- handlers to receive arguments
// so that you can onclick="steps.go" data-on-click="share"
handler: function (target, event, binding) {
var eventType = binding.args[0];
var arg = target.getAttribute('data-on-' + eventType);
if (arg) {
this.call(binding.model, arg);
} else {
// that's rivets' default behavior afaik
this.call(binding.model, event, binding);
}
}
});
With this configuration enabled, the first and only argument sent to the rv-on-click handler is the value specified by data-on-click.
<a rv-on-click="steps.go" data-on-click="homePage">home</a>
This is not my code (I found it here), but it does work with Rivets 0.8.1.
There is also a way to pass the current context to the event handler. Basically, when an event fires, the first argument passed to the handler is the event itself (click, etc), and the second argument is the model context.
So lets say that you are dealing with a model object that is the product of a rv-each loop...
<div rv-each-group="menu.groups">
<input rv-input="group.name"><button rv-on-click="vm.addItem">Add item</button>
___ more code here ___
</div>
Then you can access the current "group" object in the event handler like this:
var viewModel = {
addItem: function(ev, view) {
var group = view.group;
}
};
More details on this technique can he found here https://github.com/mikeric/rivets/pull/162
I hope this helps.
There is another answer here:
https://github.com/mikeric/rivets/issues/682
by Namek:
You could define args formatter:
rivets.formatters.args = function(fn) {
let args = Array.prototype.slice.call(arguments, 1)
return () => fn.apply(null, args)
}
and then:
rv-on-click="on_click | args 1"
Please note that args is not a special id, you can define anything instead of args.
To pass multiple arguments use space: "on_click | args 1 2 3 'str'"
I was wondering if anyone can help me understand how exactly to create different Custom event listeners.
I don't have a specific case of an event but I want to learn just in general how it is done, so I can apply it where it is needed.
What I was looking to do, just incase some folks might need to know, was:
var position = 0;
for(var i = 0; i < 10; i++)
{
position++;
if((position + 1) % 4 == 0)
{
// do some functions
}
}
var evt = document.createEvent("Event");
evt.initEvent("myEvent",true,true);
// custom param
evt.foo = "bar";
//register
document.addEventListener("myEvent",myEventHandler,false);
//invoke
document.dispatchEvent(evt);
Here is the way to do it more locally, pinpointing listeners and publishers:
http://www.kaizou.org/2010/03/generating-custom-javascript-events/
Implementing custom events is not hard. You can implement it in many ways. Lately I'm doing it like this:
/***************************************************************
*
* Observable
*
***************************************************************/
var Observable;
(Observable = function() {
}).prototype = {
listen: function(type, method, scope, context) {
var listeners, handlers;
if (!(listeners = this.listeners)) {
listeners = this.listeners = {};
}
if (!(handlers = listeners[type])){
handlers = listeners[type] = [];
}
scope = (scope ? scope : window);
handlers.push({
method: method,
scope: scope,
context: (context ? context : scope)
});
},
fireEvent: function(type, data, context) {
var listeners, handlers, i, n, handler, scope;
if (!(listeners = this.listeners)) {
return;
}
if (!(handlers = listeners[type])){
return;
}
for (i = 0, n = handlers.length; i < n; i++){
handler = handlers[i];
if (typeof(context)!=="undefined" && context !== handler.context) continue;
if (handler.method.call(
handler.scope, this, type, data
)===false) {
return false;
}
}
return true;
}
};
The Observable object can be reused and applied by whatever constructor needs it simply by mixng the prototype of Observable with the protoype of that constructor.
To start listening, you have to register yourself to the observable object, like so:
var obs = new Observable();
obs.listen("myEvent", function(observable, eventType, data){
//handle myEvent
});
Or if your listener is a method of an object, like so:
obs.listen("myEvent", listener.handler, listener);
Where listener is an instance of an object, which implements the method "handler".
The Observable object can now call its fireEvent method whenever something happens that it wants to communicate to its listeners:
this.fireEvent("myEvent", data);
Where data is some data that the listeners my find interesting. Whatever you put in there is up to you - you know best what your custom event is made up of.
The fireEvent method simply goes through all the listeners that were registered for "myEvent", and calls the registered function. If the function returns false, then that is taken to mean that the event is canceled, and the observable will not call the other listeners. As a result the entire fireEvent method will return fasle too so the observable knows that whatever action it was notifying its listeners of should now be rolled back.
Perhaps this solution doesn't suit everybody, but I;ve had much benefit from this relatively simple piece of code.
From here:
https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Creating_and_triggering_events
// create the event
const event = new Event('build');
// elem is any element
elem.dispatchEvent(event);
// later on.. binding to that event
// we'll bind to the document for the event delegation style.
document.addEventListener('build', function(e){
// e.target matches the elem from above
}, false);
Here is a really simple (TypeScript/Babelish) implementation:
const simpleEvent = <T extends Function>(context = null) => {
let cbs: T[] = [];
return {
addListener: (cb: T) => { cbs.push(cb); },
removeListener: (cb: T) => { let i = cbs.indexOf(cb); cbs.splice(i, Math.max(i, 0)); },
trigger: (<T> (((...args) => cbs.forEach(cb => cb.apply(context, args))) as any))
};
};
You use it like this:
let onMyEvent = simpleEvent();
let listener = (test) => { console.log("triggered", test); };
onMyEvent.addListener(listener);
onMyEvent.trigger("hello");
onMyEvent.removeListener(listener);
Or in classes like this
class Example {
public onMyEvent = simpleEvent(this);
}
If you want plain JavaScript you can transpile it using TypeScript playground.
I've started to write few jQuery plugins and figured it'd be nice to setup my IDE with a jQuery plugin template.
I have been reading some articles and posts on this site related to plugin convention, design, etc.. and thought I'd try and consolidate all of that.
Below is my template, I am looking to use it frequently so was keen to ensure it generally conforms to jQuery plugin design convention and whether the idea of having multiple internal methods (or even its general design) would impact performance and be prone to memory issues.
(function($)
{
var PLUGIN_NAME = "myPlugin"; // TODO: Plugin name goes here.
var DEFAULT_OPTIONS =
{
// TODO: Default options for plugin.
};
var pluginInstanceIdCount = 0;
var I = function(/*HTMLElement*/ element)
{
return new Internal(element);
};
var Internal = function(/*HTMLElement*/ element)
{
this.$elem = $(element);
this.elem = element;
this.data = this.getData();
// Shorthand accessors to data entries:
this.id = this.data.id;
this.options = this.data.options;
};
/**
* Initialises the plugin.
*/
Internal.prototype.init = function(/*Object*/ customOptions)
{
var data = this.getData();
if (!data.initialised)
{
data.initialised = true;
data.options = $.extend(DEFAULT_OPTIONS, customOptions);
// TODO: Set default data plugin variables.
// TODO: Call custom internal methods to intialise your plugin.
}
};
/**
* Returns the data for relevant for this plugin
* while also setting the ID for this plugin instance
* if this is a new instance.
*/
Internal.prototype.getData = function()
{
if (!this.$elem.data(PLUGIN_NAME))
{
this.$elem.data(PLUGIN_NAME, {
id : pluginInstanceIdCount++,
initialised : false
});
}
return this.$elem.data(PLUGIN_NAME);
};
// TODO: Add additional internal methods here, e.g. Internal.prototype.<myPrivMethod> = function(){...}
/**
* Returns the event namespace for this widget.
* The returned namespace is unique for this widget
* since it could bind listeners to other elements
* on the page or the window.
*/
Internal.prototype.getEventNs = function(/*boolean*/ includeDot)
{
return (includeDot !== false ? "." : "") + PLUGIN_NAME + "_" + this.id;
};
/**
* Removes all event listeners, data and
* HTML elements automatically created.
*/
Internal.prototype.destroy = function()
{
this.$elem.unbind(this.getEventNs());
this.$elem.removeData(PLUGIN_NAME);
// TODO: Unbind listeners attached to other elements of the page and window.
};
var publicMethods =
{
init : function(/*Object*/ customOptions)
{
return this.each(function()
{
I(this).init(customOptions);
});
},
destroy : function()
{
return this.each(function()
{
I(this).destroy();
});
}
// TODO: Add additional public methods here.
};
$.fn[PLUGIN_NAME] = function(/*String|Object*/ methodOrOptions)
{
if (!methodOrOptions || typeof methodOrOptions == "object")
{
return publicMethods.init.call(this, methodOrOptions);
}
else if (publicMethods[methodOrOptions])
{
var args = Array.prototype.slice.call(arguments, 1);
return publicMethods[methodOrOptions].apply(this, args);
}
else
{
$.error("Method '" + methodOrOptions + "' doesn't exist for " + PLUGIN_NAME + " plugin");
}
};
})(jQuery);
Thanks in advance.
A while back I've build a plugin generator based on a blog article I have read: http://jsfiddle.net/KeesCBakker/QkPBF/. It might be of use. It is fairly basic and straight forward. Any comments would be very welcome.
You can fork your own generator and change it to your needs.
Ps. This is the generated body:
(function($){
//My description
function MyPluginClassName(el, options) {
//Defaults:
this.defaults = {
defaultStringSetting: 'Hello World',
defaultIntSetting: 1
};
//Extending options:
this.opts = $.extend({}, this.defaults, options);
//Privates:
this.$el = $(el);
}
// Separate functionality from object creation
MyPluginClassName.prototype = {
init: function() {
var _this = this;
},
//My method description
myMethod: function() {
var _this = this;
}
};
// The actual plugin
$.fn.myPluginClassName = function(options) {
if(this.length) {
this.each(function() {
var rev = new MyPluginClassName(this, options);
rev.init();
$(this).data('myPluginClassName', rev);
});
}
};
})(jQuery);
[Edit] 7 months later
Quoting from the github project
jQuery is no good, and jQuery plugins is not how do modular code.
Seriously "jQuery plugins" are not a sound architecture strategy. Writing code with a hard dependency on jQuery is also silly.
[Original]
Since I gave critique about this template I will propose an alternative.
To make live easier this relies on jQuery 1.6+ and ES5 (use the ES5 Shim).
I've spend some time re-designing the plugin template you've given and rolled out my own.
Links:
Github
Documentation
Unit tests Confirmed to pass in FF4, Chrome and IE9 (IE8 & OP11 dies. known bug).
Annotated Source Code
The PlaceKitten example plugin
Comparison:
I've refactored the template so that it's split into boilerplate (85%) and scaffolding code (15%). The intention is that you only have to edit the scaffolding code and you can keep leave boilerplate code untouched. To achieve this I've used
inheritance var self = Object.create(Base) Rather then editing the Internal class you have directly you should be editing a sub class. All your template / default functionality should be in a base class (called Base in my code).
convention self[PLUGIN_NAME] = main; By convention the plugin defined on jQuery will call the method define on self[PLUGIN_NAME] by default. This is considered the main plugin method and has a seperate external method for clarity.
monkey patching $.fn.bind = function _bind ... Use of monkey patching means that the event namespacing is done automatically for you under the hood. This functionality is free and does not come at the cost of readability (calling getEventNS all the time).
OO Techniques
It's better to stick to proper JavaScript OO rather then classical OO emulation. To achieve this you should use Object.create. (which ES5 just use the shim to upgrade old browsers).
var Base = (function _Base() {
var self = Object.create({});
/* ... */
return self;
})();
var Wrap = (function _Wrap() {
var self = Object.create(Base);
/* ... */
return self;
})();
var w = Object.create(Wrap);
This is different from the standard new and .prototype based OO people are used to. This approach is preferred because it re-inforces the concept that there are only Objects in JavaScript and it's a prototypical OO approach.
[getEventNs]
As mentioned this method has been refactored away by overriding .bind and .unbind to automatically inject namespaces. These methods are overwritten on the private version of jQuery $.sub(). The overwritten methods behave the same way as your namespacing does. It namespaces events uniquely based on plugin and instance of a plugin wrapper around a HTMLElement (Using .ns.
[getData]
This method has been replaced with a .data method that has the same API as jQuery.fn.data. The fact that it's the same API makes it easier to use, its basically a thin wrapper around jQuery.fn.data with namespacing. This allows you to set key/value pair data that is immediatley stored for that plugin only. Multiple plugins can use this method in parallel without any conflicts.
[publicMethods]
The publicMethods object has been replaced by any method being defined on Wrap being automatically public. You can call any method on a Wrapped object directly but you do not actually have access to the wrapped object.
[$.fn[PLUGIN_NAME]]
This has been refactored so it exposes a more standardized API. This api is
$(selector).PLUGIN_NAME("methodName", {/* object hash */}); // OR
$(selector).PLUGIN_NAME({/* object hash */}); // methodName defaults to PLUGIN_NAME
the elements in the selector are automatically wrapped in the Wrap object, the method is called or each selected element from the selector and the return value is always a $.Deferred element.
This standardizes the API and the return type. You can then call .then on the returned deferred to get out the actual data you care about. The use of deferred here is very powerful for abstraction away whether the plugin is synchronous or asynchronous.
_create
A caching create function has been added. This is called to turn a HTMLElement into a Wrapped element and each HTMLElement will only be wrapped once. This caching gives you a solid reduction in memory.
$.PLUGIN_NAME
Added another public method for the plugin (A total of two!).
$.PLUGIN_NAME(elem, "methodName", {/* options */});
$.PLUGIN_NAME([elem, elem2, ...], "methodName", {/* options */});
$.PLUGIN_NAME("methodName", {
elem: elem, /* [elem, elem2, ...] */
cb: function() { /* success callback */ }
/* further options */
});
All parameters are optional. elem defaults to <body>, "methodName" defaults to "PLUGIN_NAME" and {/* options */} defaults to {}.
This API is very flexible (with 14 method overloads!) and standard enough to get used to the syntnax for every method your plugin will expose.
Public exposure
The Wrap, create and $ objects are exposed globally. This will allow advanced plugin users maximum flexibility with your plugin. They can use create and the modified subbed $ in their development and they can also monkey patch Wrap. This allows for i.e. hooking into your plugin methods. All three of these are marked with a _ in front of their name so they are internal and using them breaks the garantuee that your plugin works.
The internal defaults object is also exposed as $.PLUGIN_NAME.global. This allows users to override your defaults and set plugin global defaults. In this plugin setup all hashes past into methods as objects are merged with the defaults, so this allows users to set global defaults for all your methods.
Actual Code
(function($, jQuery, window, document, undefined) {
var PLUGIN_NAME = "Identity";
// default options hash.
var defaults = {
// TODO: Add defaults
};
// -------------------------------
// -------- BOILERPLATE ----------
// -------------------------------
var toString = Object.prototype.toString,
// uid for elements
uuid = 0,
Wrap, Base, create, main;
(function _boilerplate() {
// over-ride bind so it uses a namespace by default
// namespace is PLUGIN_NAME_<uid>
$.fn.bind = function _bind(type, data, fn, nsKey) {
if (typeof type === "object") {
for (var key in type) {
nsKey = key + this.data(PLUGIN_NAME)._ns;
this.bind(nsKey, data, type[key], fn);
}
return this;
}
nsKey = type + this.data(PLUGIN_NAME)._ns;
return jQuery.fn.bind.call(this, nsKey, data, fn);
};
// override unbind so it uses a namespace by default.
// add new override. .unbind() with 0 arguments unbinds all methods
// for that element for this plugin. i.e. calls .unbind(_ns)
$.fn.unbind = function _unbind(type, fn, nsKey) {
// Handle object literals
if ( typeof type === "object" && !type.preventDefault ) {
for ( var key in type ) {
nsKey = key + this.data(PLUGIN_NAME)._ns;
this.unbind(nsKey, type[key]);
}
} else if (arguments.length === 0) {
return jQuery.fn.unbind.call(this, this.data(PLUGIN_NAME)._ns);
} else {
nsKey = type + this.data(PLUGIN_NAME)._ns;
return jQuery.fn.unbind.call(this, nsKey, fn);
}
return this;
};
// Creates a new Wrapped element. This is cached. One wrapped element
// per HTMLElement. Uses data-PLUGIN_NAME-cache as key and
// creates one if not exists.
create = (function _cache_create() {
function _factory(elem) {
return Object.create(Wrap, {
"elem": {value: elem},
"$elem": {value: $(elem)},
"uid": {value: ++uuid}
});
}
var uid = 0;
var cache = {};
return function _cache(elem) {
var key = "";
for (var k in cache) {
if (cache[k].elem == elem) {
key = k;
break;
}
}
if (key === "") {
cache[PLUGIN_NAME + "_" + ++uid] = _factory(elem);
key = PLUGIN_NAME + "_" + uid;
}
return cache[key]._init();
};
}());
// Base object which every Wrap inherits from
Base = (function _Base() {
var self = Object.create({});
// destroy method. unbinds, removes data
self.destroy = function _destroy() {
if (this._alive) {
this.$elem.unbind();
this.$elem.removeData(PLUGIN_NAME);
this._alive = false;
}
};
// initializes the namespace and stores it on the elem.
self._init = function _init() {
if (!this._alive) {
this._ns = "." + PLUGIN_NAME + "_" + this.uid;
this.data("_ns", this._ns);
this._alive = true;
}
return this;
};
// returns data thats stored on the elem under the plugin.
self.data = function _data(name, value) {
var $elem = this.$elem, data;
if (name === undefined) {
return $elem.data(PLUGIN_NAME);
} else if (typeof name === "object") {
data = $elem.data(PLUGIN_NAME) || {};
for (var k in name) {
data[k] = name[k];
}
$elem.data(PLUGIN_NAME, data);
} else if (arguments.length === 1) {
return ($elem.data(PLUGIN_NAME) || {})[name];
} else {
data = $elem.data(PLUGIN_NAME) || {};
data[name] = value;
$elem.data(PLUGIN_NAME, data);
}
};
return self;
})();
// Call methods directly. $.PLUGIN_NAME(elem, "method", option_hash)
var methods = jQuery[PLUGIN_NAME] = function _methods(elem, op, hash) {
if (typeof elem === "string") {
hash = op || {};
op = elem;
elem = hash.elem;
} else if ((elem && elem.nodeType) || Array.isArray(elem)) {
if (typeof op !== "string") {
hash = op;
op = null;
}
} else {
hash = elem || {};
elem = hash.elem;
}
hash = hash || {}
op = op || PLUGIN_NAME;
elem = elem || document.body;
if (Array.isArray(elem)) {
var defs = elem.map(function(val) {
return create(val)[op](hash);
});
} else {
var defs = [create(elem)[op](hash)];
}
return $.when.apply($, defs).then(hash.cb);
};
// expose publicly.
Object.defineProperties(methods, {
"_Wrap": {
"get": function() { return Wrap; },
"set": function(v) { Wrap = v; }
},
"_create":{
value: create
},
"_$": {
value: $
},
"global": {
"get": function() { return defaults; },
"set": function(v) { defaults = v; }
}
});
// main plugin. $(selector).PLUGIN_NAME("method", option_hash)
jQuery.fn[PLUGIN_NAME] = function _main(op, hash) {
if (typeof op === "object" || !op) {
hash = op;
op = null;
}
op = op || PLUGIN_NAME;
hash = hash || {};
// map the elements to deferreds.
var defs = this.map(function _map() {
return create(this)[op](hash);
}).toArray();
// call the cb when were done and return the deffered.
return $.when.apply($, defs).then(hash.cb);
};
}());
// -------------------------------
// --------- YOUR CODE -----------
// -------------------------------
main = function _main(options) {
this.options = options = $.extend(true, defaults, options);
var def = $.Deferred();
// Identity returns this & the $elem.
// TODO: Replace with custom logic
def.resolve([this, this.elem]);
return def;
}
Wrap = (function() {
var self = Object.create(Base);
var $destroy = self.destroy;
self.destroy = function _destroy() {
delete this.options;
// custom destruction logic
// remove elements and other events / data not stored on .$elem
$destroy.apply(this, arguments);
};
// set the main PLUGIN_NAME method to be main.
self[PLUGIN_NAME] = main;
// TODO: Add custom logic for public methods
return self;
}());
})(jQuery.sub(), jQuery, this, document);
As can be seen the code your supposed to edit is below the YOUR CODE line. The Wrap object acts similarly to your Internal object.
The function main is the main function called with $.PLUGIN_NAME() or $(selector).PLUGIN_NAME() and should contain your main logic.
How about something like this ? It's much clearer but again it would be nice to hear from you if you can improve it without overcomplicating its simplicity.
// jQuery plugin Template
(function($){
$.myPlugin = function(options) { //or use "$.fn.myPlugin" or "$.myPlugin" to call it globaly directly from $.myPlugin();
var defaults = {
target: ".box",
buttons: "li a"
};
options = $.extend(defaults, options);
function logic(){
// ... code goes here
}
//DEFINE WHEN TO RUN THIS PLUGIN
$(window).on('load resize', function () { // Load and resize as example ... use whatever you like
logic();
});
// RETURN OBJECT FOR CHAINING
// return this;
// OR FOR FOR MULTIPLE OBJECTS
// return this.each(function() {
// // Your code ...
// });
};
})(jQuery);
// USE EXAMPLE with default settings
$.myPlugin(); // or run plugin with default settings like so.
// USE EXAMPLE with overwriten settings
var options = {
target: "div.box", // define custom options
buttons: ".something li a" // define custom options
}
$.myPlugin(options); //or run plugin with overwriten default settings
I've been googling and landed here so, I have to post some ideas: first I agree with #Raynos.
The most code out there that tries to build a jQuery plugin actually...is not a plugin! It's just an object stored in memory which is refered by the data property of a node/element. That's because jQuery should be seen and used as a tool side by side with a class library (to remedy js inconsistencies from OO architecture) to build better code and yes this is not bad at all!
If you don't like classical OO behaviour stick to a prototypal library like clone.
So what our options really?
use JQueryUI/Widget or a similar library that hides technicalities and
provides abstraction
don't use them because of complexities, learning curve and god knows future changes
don't use them becuase you want to insist on modular design, build small-increase later
don't use them because you might want porting/connecting your code with different libraries.
Suppose the issues addressed by the following scenario (see the complexities from this question: Which jQuery plugin design pattern should I use?):
we have nodes A, B and C that store an object reference into their data property
some of them store info in public and private accessible internal objects,
some classes of these objects are connected with inheritance,
all of these nodes also need some private and public singletons to work best.
What would we do? See the drawning:
classes : | A B C
------------------case 1----------
members | | | |
of | v v v
an object | var a=new A, b=new B, c=new C
at | B extends A
node X : | a, b, c : private
------------------case 2---------
members | | | |
of | v v v
an object | var aa=new A, bb=new B, cc=new C
at | BB extends AA
node Y : | aa, bb, cc : public
-------------------case 3--------
members | | | |
of | v v v
an object | var d= D.getInstance() (private),
at | e= E.getInstance() (public)
node Z : | D, E : Singletons
as you can see every node refers to an object - a jQuery approach - but these objects change wildely; they contain object-properties with different data stored in or, even singletons that should be...single in memory like the prototype functions of the objects. We don't want every object's function belonging to class A to be repeatedly duplicated in memory in every node's object!
Before my answer see a common approach I've seen in jQuery plugins - some of them very popular but I don't say names:
(function($, window, document, undefined){
var x = '...', y = '...', z = '...',
container, $container, options;
var myPlugin = (function(){ //<----the game is lost!
var defaults = {
};
function init(elem, options) {
container = elem;
$container = $(elem);
options = $.extend({}, defaults, options);
}
return {
pluginName: 'superPlugin',
init: function(elem, options) {
init(elem, options);
}
};
})();
//extend jquery
$.fn.superPlugin = function(options) {
return this.each(function() {
var obj = Object.create(myPlugin); //<---lose, lose, lose!
obj.init(this, options);
$(this).data(obj.pluginName, obj);
});
};
}(jQuery, window, document));
I was watching some slides at: http://www.slideshare.net/benalman/jquery-plugin-creation from Ben Alman where he refers at slide 13 to object literals as singletons and that just knock me over: this is what the above plugin does, it creates one singleton with no chance whatsover to alter it's internal state!!!
Furthermore, at the jQuery part it stores a common reference to every single node!
My solution uses a factory to keep internal state and return an object plus it can be expanded with a class library and split in different files:
;(function($, window, document, undefined){
var myPluginFactory = function(elem, options){
........
var modelState = {
options: null //collects data from user + default
};
........
function modeler(elem){
modelState.options.a = new $$.A(elem.href);
modelState.options.b = $$.B.getInstance();
};
........
return {
pluginName: 'myPlugin',
init: function(elem, options) {
init(elem, options);
},
get_a: function(){return modelState.options.a.href;},
get_b: function(){return modelState.options.b.toString();}
};
};
//extend jquery
$.fn.myPlugin = function(options) {
return this.each(function() {
var plugin = myPluginFactory(this, options);
$(this).data(plugin.pluginName, plugin);
});
};
}(jQuery, window, document));
My project: https://github.com/centurianii/jsplugin
See: http://jsfiddle.net/centurianii/s4J2H/1/