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The Problem
This answer has been answered before but are old and not up to date. I have over 2000 lines of code in a single file, and as we all know this is bad practice, especially when i'm looking through code or adding new features. I want to better organize my code, for now and for the future.
I should mention that I'm building a tool (not a simple website) with lots of buttons, UI elements, drag, drops, action listeners/handlers and function in the global scope where several listeners may use the same function.
Example code
$('#button1').on('click', function(e){
// Determined action.
update_html();
});
... // Around 75 more of this
function update_html(){ .... }
...
More example code
Conclusion
I really need to organize this code for best use and not to repeat myself and be able to add new features and update old ones. I will be working on this by myself. Some selectors can be 100 lines of code others are 1. I have looked a bit at require.js and found it kinda repetitive, and actually writing more code than needed . I'm open to any possible solution that fit this criteria and link to resource / examples are always a plus.
Thanks.
I'll go over some simple things that may, or may not, help you. Some might be obvious, some might be extremely arcane.
Step 1: Compartmentalize your code
Separating your code into multiple, modular units is a very good first step. Round up what works "together" and put them in their own little encased unit. don't worry about the format for now, keep it inline. The structure is a later point.
So, suppose you have a page like this:
It would make sense to compartmentalize so that all the header-related event handlers/binders are in there, for ease of maintenance (and not having to sift through 1000 lines).
You can then use a tool such as Grunt to re-build your JS back to a single unit.
Step 1a: Dependency management
Use a library such as RequireJS or CommonJS to implement something called AMD. Asynchronous Module Loading allows you to explicitely state what your code depends on, which then allows you to offload the library-calling to the code. You can just literally say "This needs jQuery" and the AMD will load it, and execute your code when jQuery is available.
This also has a hidden gem: the library loading will be done the second the DOM is ready, not before. This no longer halts load-up of your page!
Step 2: Modularize
See the wireframe? I have two ad units. They'll most likely have shared event listeners.
Your task in this step is to identify the points of repetition in your code and to try to synthesise all this into modules. Modules, right now, will encompass everything. We'll split stuff as we go along.
The whole idea of this step is to go from step 1 and delete all the copy-pastas, to replace them with units that are loosely coupled. So, instead of having:
ad_unit1.js
$("#au1").click(function() { ... });
ad_unit2.js
$("#au2").click(function() { ... });
I will have:
ad_unit.js:
var AdUnit = function(elem) {
this.element = elem || new jQuery();
}
AdUnit.prototype.bindEvents = function() {
... Events go here
}
page.js:
var AUs = new AdUnit($("#au1,#au2"));
AUs.bindEvents();
Which allows you to compartmentalize between your events and your markup in addition to getting rid of repetition. This is a pretty decent step and we'll extend this further later on.
Step 3: Pick a framework!
If you'd like to modularize and reduce repetitions even further, there are a bunch of awesome frameworks around that implement MVC (Model - View - Controller) approaches. My favourite is Backbone/Spine, however, there's also Angular, Yii, ... The list goes on.
A Model represents your data.
A View represents your mark-up and all the events associated to it
A Controller represents your business logic - in other words, the controller tells the page what views to load and what models to use.
This will be a significant learning step, but the prize is worth it: it favours clean, modular code over spaghetti.
There are plenty of other things you can do, those are just guidelines and ideas.
Code-specific changes
Here are some specific improvements to your code:
$('.new_layer').click(function(){
dialog("Create new layer","Enter your layer name","_input", {
'OK' : function(){
var reply = $('.dialog_input').val();
if( reply != null && reply != "" ){
var name = "ln_"+reply.split(' ').join('_');
var parent = "";
if(selected_folder != "" ){
parent = selected_folder+" .content";
}
$R.find(".layer").clone()
.addClass(name).html(reply)
.appendTo("#layer_groups "+parent);
$R.find(".layers_group").clone()
.addClass(name).appendTo('#canvas '+selected_folder);
}
}
});
});
This is better written as:
$("body").on("click",".new_layer", function() {
dialog("Create new layer", "Enter your layer name", "_input", {
OK: function() {
// There must be a way to get the input from here using this, if it is a standard library. If you wrote your own, make the value retrievable using something other than a class selector (horrible performance + scoping +multiple instance issues)
// This is where the view comes into play. Instead of cloning, bind the rendering into a JS prototype, and instantiate it. It means that you only have to modify stuff in one place, you don't risk cloning events with it, and you can test your Layer stand-alone
var newLayer = new Layer();
newLayer
.setName(name)
.bindToGroup(parent);
}
});
});
Earlier in your code:
window.Layer = function() {
this.instance = $("<div>");
// Markup generated here
};
window.Layer.prototype = {
setName: function(newName) {
},
bindToGroup: function(parentNode) {
}
}
Suddenly, you have a way to create a standard layer from anywhere in your code without copy pasting. You're doing this in five different places. I've just saved you five copy-pastes.
One more:
// Ruleset wrapper for actions
var PageElements = function(ruleSet) {
ruleSet = ruleSet || [];
this.rules = [];
for (var i = 0; i < ruleSet.length; i++) {
if (ruleSet[i].target && ruleSet[i].action) {
this.rules.push(ruleSet[i]);
}
}
}
PageElements.prototype.run = function(elem) {
for (var i = 0; i < this.rules.length; i++) {
this.rules[i].action.apply(elem.find(this.rules.target));
}
}
var GlobalRules = new PageElements([
{
"target": ".draggable",
"action": function() { this.draggable({
cancel: "div#scrolling, .content",
containment: "document"
});
}
},
{
"target" :".resizable",
"action": function() {
this.resizable({
handles: "all",
zIndex: 0,
containment: "document"
});
}
}
]);
GlobalRules.run($("body"));
// If you need to add elements later on, you can just call GlobalRules.run(yourNewElement);
This is a very potent way to register rules if you have events that are not standard, or creation events. This is also seriously kick-ass when combined with a pub/sub notification system and when bound to an event you fire whenever you create elements. Fire'n'forget modular event binding!
Here is a simple way to split your current codebase into multiple files, using require.js.
I will show you how to split your code into two files. Adding more files will be straightforward after that.
Step 1) At the top of your code, create an App object (or whatever name you prefer, like MyGame):
var App = {}
Step 2) Convert all of your top-level variables and functions to belong to the App object.
Instead of:
var selected_layer = "";
You want:
App.selected_layer = "";
Instead of:
function getModified(){
...
}
You want:
App.getModified = function() {
}
Note that at this point your code will not work until you finish the next step.
Step 3) Convert all global variable and function references to go through App.
Change stuff like:
selected_layer = "."+classes[1];
to:
App.selected_layer = "."+classes[1];
and:
getModified()
to:
App.GetModified()
Step 4) Test Your code at this stage -- it should all work. You will probably get a few errors at first because you missed something, so fix those before moving on.
Step 5) Set up requirejs. I assume you have a web page, served from a web server, whose code is in:
www/page.html
and jquery in
www/js/jquery.js
If these paths are not exactly like this the below will not work and you'll have to modify the paths.
Download requirejs and put require.js in your www/js directory.
in your page.html, delete all script tags and insert a script tag like:
<script data-main="js/main" src="js/require.js"></script>
create www/js/main.js with content:
require.config({
"shim": {
'jquery': { exports: '$' }
}
})
require(['jquery', 'app']);
then put all the code you just fixed up in Steps 1-3 (whose only global variable should be App) in:
www/js/app.js
At the very top of that file, put:
require(['jquery'], function($) {
At the bottom put:
})
Then load page.html in your browser. Your app should work!
Step 6) Create another file
Here is where your work pays off, you can do this over and over.
Pull out some code from www/js/app.js that references $ and App.
e.g.
$('a').click(function() { App.foo() }
Put it in www/js/foo.js
At the very top of that file, put:
require(['jquery', 'app'], function($, App) {
At the bottom put:
})
Then change the last line of www/js/main.js to:
require(['jquery', 'app', 'foo']);
That's it! Do this every time you want to put code in its own file!
For your question and comments I'll assume you are not willing to port your code to a framework like Backbone, or use a loader library like Require. You just want a better way to orgainze the code that you already have, in the simplest way possible.
I understand it is annoying to scroll through 2000+ lines of code to find the section that you want to work on. The solution is to split your code in different files, one for each functionality. For example sidebar.js, canvas.js etc. Then you can join them together for production using Grunt, together with Usemin you can have something like this:
In your html:
<!-- build:js scripts/app.js -->
<script src="scripts/sidebar.js"></script>
<script src="scripts/canvas.js"></script>
<!-- endbuild -->
In your Gruntfile:
useminPrepare: {
html: 'app/index.html',
options: {
dest: 'dist'
}
},
usemin: {
html: ['dist/{,*/}*.html'],
css: ['dist/styles/{,*/}*.css'],
options: {
dirs: ['dist']
}
}
If you want to use Yeoman it will give you a boilerplate code for all this.
Then for each file itself, you need to make sure you follow best practices and that all the code and variables are all in that file, and don't depend on other files. This doesn't mean you can't call functions of one file from other, the point is to have variables and functions encapsulated. Something similar to namespacing. I'll assume you don't want to port all your code to be Object Oriented, but if you don't mind refactoring a bit, I'd recommend to add something equivalent with what is called a Module pattern. It looks something like this:
sidebar.js
var Sidebar = (function(){
// functions and vars here are private
var init = function(){
$("#sidebar #sortable").sortable({
forceHelperSize: true,
forcePlaceholderSize: true,
revert: true,
revert: 150,
placeholder: "highlight panel",
axis: "y",
tolerance: "pointer",
cancel: ".content"
}).disableSelection();
}
return {
// here your can put your "public" functions
init : init
}
})();
Then you can load this bit of code like this:
$(document).ready(function(){
Sidebar.init();
...
This will allow you to have a much more maintainable code without having to rewrite your code too much.
Use javascript MVC Framework in order to organize the javascript code in a standard way.
Best JavaScript MVC frameworks available are:
Backbone
Angular
CanJS
Ember
ReactJS
Selecting a JavaScript MVC framework required so many factors to consider. Read the following comparison article that will help you to select best framework based on the factors important for your project:
http://sporto.github.io/blog/2013/04/12/comparison-angular-backbone-can-ember/
You can also use RequireJS with the framework to support Asynchrounous js file & module loading.
Look the below to get started on JS Module loading:
http://www.sitepoint.com/understanding-requirejs-for-effective-javascript-module-loading/
Categorize your code. This method is helping me a lot and does work with any js framework:
(function(){//HEADER: menu
//your code for your header
})();
(function(){//HEADER: location bar
//your code for your location
})();
(function(){//FOOTER
//your code for your footer
})();
(function(){//PANEL: interactive links. e.g:
var crr = null;
$('::section.panel a').addEvent('click', function(E){
if ( crr) {
crr.hide();
}
crr = this.show();
});
})();
In your preferred editor (the best is Komodo Edit) you may fold in by collapsing all entries and you will see only the titles:
(function(){//HEADER: menu_____________________________________
(function(){//HEADER: location bar_____________________________
(function(){//FOOTER___________________________________________
(function(){//PANEL: interactive links. e.g:___________________
I would suggest:
publisher/subscriber pattern for event management.
object orientation
namespacing
In your case Jessica, divide the interface into pages or screens. Pages or screens can be objects and extended from some parent classes. Manage the interactions among pages with a PageManager class.
I suggest that you use something like Backbone. Backbone is a RESTFUL supported javascript library. Ik makes your code cleaner and more readable and is powerful when used together with requirejs.
http://backbonejs.org/
http://requirejs.org/
Backbone isn't a real library. It is meant to give structure to your javascript code. It is able to include other libraries like jquery, jquery-ui, google-maps etc. Backbone is in my opinion the closest javascript approach to Object Oriented and Model View Controller structures.
Also regarding your workflow.. If you build your applications in PHP use the Laravel library. It'll work flawlessly with Backbone when used with the RESTfull principle. Below the link to Laravel Framework and a tutorial about building RESTfull APIs:
http://maxoffsky.com/code-blog/building-restful-api-in-laravel-start-here/
http://laravel.com/
Below is a tutorial from nettuts. Nettuts has a lot of High Quality tutorials:
http://net.tutsplus.com/tutorials/javascript-ajax/understanding-backbone-js-and-the-server/
Maybe its time for you start implementing a whole development workflow using such tools as yeoman http://yeoman.io/. This will help control all your dependencies, build process and if you wanted, automated testing. Its a lot of work to start with but once implemented will make future changes a lot easier.
These days I find myself putting a lot of my code in the $(document).ready() which does not seem clean to me. For example, if I am creating something that will query my database via ajax and return it and append it to my list i would do something like this:
$(function(){
//Initialize my DOM elements
$MyList = $("#MyList"),
$MyButton = $("#MyButton");
//Add my Click event
$MyButton.click(function(){
$.ajax({
type: 'POST',
url: "/lists/getmylist",
contentType: "application/json",
success: function(results){
//Parse my results and append them using my favorite templating helper
var jsonResults = $.parseJSON(result);
$MyList.mustache("my-template", jsonResults);
}
});
})
});
Now I know this is a small example but it starts to get really big and messy when I have multiple click events, ajax requests etc. It all ends up going in my document ready. I know that I can possibly put all my ajax requests in an external javascript file to help make it cleaner, but is this architecture in general ok? just seems like its really messy. I have seen others use plugin architectures or init functions. I usually have this document ready at the bottom of all my pages and just throw in whatever is necessary to make my page work correctly. Is this a good way to structure my js?
I think the addition of some Model objects and general object oriented programming principals might go a long way here. If you break your your data fetching and storing out into model classes it should help a lot.
Here are some links that should get you started thinking about OO with Javascript.
Writing Object-Oriented JavaScript
Javascript Design Patterns
Javascript: prototypal inheritance
Javascript: prototypal inheritance 2
Another thing that might help out would be to break the Javascript into multiple files. One for global scripts that might be included via a header that attaches to all your pages and a script for each of your pages that requires it.
Perhaps Backbone.js ( or one of the other frameworks ) could be part of the rescue you are looking for.
I found Backbone immensely helpful organising some inherited spaghetti. Your starting point might be to transition your massive document ready into a backbone view (or multiples of)
Organise your scripts by separating out the views, collections, models into individual files then bundle and minify them together into a single file so the browser only needs to make one request instead of many.
ASP.NET MVC4 can do the bundling for you, it also works similarly on MVC3
This is just a example of simple starting point, there are more advanced techniques (eg. AMD, require.js) to reduce the script size per page, but with caching and gzip I find that the single everything script bundle is fine for a lot of cases.
As for your example, here's a possible backbone implementation
Remember to namespace out your code...
var app = app || {};
$(function ($) {
// depending on your server setup you might be able to just override the url
// and get away with what you want. Otherwise you might look into overriding
// the save/fetch or sync methods of the collection
app.MyListCollection = Backbone.Collection.extend({
url: '/lists/getmylist'
});
app.MyListView = Backbone.View.extend({
//bind the view to the existing element in the HTML.
el: '#MyList',
// your mustache template
template:$('#list-template').html(),
// hook up your event handlers to page components
//(within the context of your el)
events: {
'click #MyButton': 'onMyButtonClick'
},
//called on object creation.
initialize: function () {
//you could create a collection here or pass it into the init function
this.collection = new app.MyListCollection();
//when the collection is changes, call the render method
this.listenTo(this.collection, 'reset', this.render);
},
// render is named by convention, but its where you would "redraw" your view and apply your template
render: function () {
this.$el.html(
Mustache.render(
this.template(this.collection.toJSON())));
return this;
},
//your click handler
onMyButtonClick: function(e){
this.collection.fetch();
}
});
});
use your doc ready to spin up whatever backbone functionality you need
and use it bootstrap your javascript with any server side data that you may have.
$(function () {
// create an instance of your view
new app.MyListView();
//example bootstrap using razor
app.title = #Model.Title;
});
I am a complete noob to backbone and decided to try and create a web page or two based using backbone as a structure. My first task is to create a basic navigation.
My page lives here http://dalydd.com/projects/backbone.html
here is my javascript thus fur to create that one little navigation item
(function($){
var NavigationItem = Backbone.Model.extend({
defaults: {
name: '',
href: '',
last: false,
id: ''
},
initialize: function() {
}
});
var home = new NavigationItem({name: 'home', href: '/home', id:'home'});
var about = new NavigationItem({name:'about', href: '/about'});
var contact = new NavigationItem({name:'contact', href: '/contact', last:true});
var TopNav = Backbone.Collection.extend({
model: NavigationItem,
});
var topNav = new TopNav();
NavView = Backbone.View.extend({
el : $('ul'),
initialize: function(){
_.bindAll(this, 'render');
this.render();
},
render : function() {
var self = this;
$(this.el).append("<li>"+home.get('name')+"</li>")
}
});
var navView = new NavView();
})(jQuery);
My question(s) is how can i loop through each instantiated nav item and append it to the ul element w/o writing each one out
My other question is can you use backbone without data-binding your scripts, data-binding seems like obtrusive javascript in a way. Also does one need to become an expert in underscore.js in order to use backbone properly. Underscore just seems like a bunch of predefined functions - doesn't jQuery offer some of the same functions as utility functions? so why even use underscore is because of the data binding? can you use backbone w/o data-binding everything? I'm having a difficult time learning backbone because I feel like it mimics a classical language instead of using something like Object.create() like Douglas Crockford uses. Are there any resources out there that just build a basic page using backbone? I know it's not intended for small applications but I'm still trying to figure out how it all works.
Again any help/resources is appreciated. I just started working for a large corporation and they are looking to implement an MVC framework for javascript and backbone seems the ideal choice but I am struggling thus far to learn.
Underscore just seems like a bunch of predefined functions - doesn't jQuery offer some of the same functions as utility functions? so why even use underscore is because of the data binding? can you use backbone w/o data-binding everything?
Underscore doesn't deal with the DOM, only with JavaScript. The two are orthogonal.
Underscore is a backbone dependency , you need it to make it work.
jQuery/Zepto is needed if you need to work with the DOM ( and ajax ).
Underscore is used in models and collections at least , whether you use it directly or not.
I'm having a difficult time learning backbone because I feel like it mimics a classical language instead of using something like Object.create() like Douglas Crockford uses.
You need to use the library API when required , or use another lib. Backbone uses prototypal inheritance when Object.create is classical inheritance. JavaScript allows both.
My point is you don't need to use every feature of backbone, but you need to use the basic required features in order to make it work.
Backbone provides Collections for this matter. Any Backbone View can hold a Model or a Collection. In your example you could build a collection like this:
var NavigationCollection = Backbone.Collection.extend({
model : NavigationItem
});
Then, you would create the collection and append all of the items:
var navCollection = new NavigationCollection();
navCollection.add(home);
navCollection.add(about);
navCollection.add(content);
and then you can make a view which just displays it all:
var navView = new NavView({
collection : navCollection
});
being this view something like:
var NavView = Backbone.View.extend({
el : $('ul'),
initialize: function(){
_.bindAll(this, 'render');
this.render();
},
render : function() {
this.collection.each(function (item) {
this.$el.append("<li>" + item.get("name") + "</li>");
}, this);
return this; // remember this for chaining
}
});
You could have a view for displaying each of the individual items (and a subviews attribute, so you can refer to them) or even a template which iterates over this collection.
i've been playing with MVC for a while now, but since the project i'm on is starting to get wind in its sails more and more people are added to it. Since i'm in charge of hacking around to find out some "best practice", i'm especially wary about the possible misuses of javascript and would like to find out what would be the best way to have our views and partial views play nicely with javascript.
For the moment, we're having code that looks like this (only simplified for example's sake)
<script type="text/javascript">
function DisableInputsForSubmit() {
if ($('#IsDisabled').is(':checked')) {
$('#Parameters :input').attr('disabled', true);
} else {
$('#Parameters :input').removeAttr('disabled');
}
}
</script>
<%=Html.SubmitButton("submit", Html.ResourceText("submit"), New With {.class = "button", .onclick = "DisableInputsForSubmit(); if ($('#EditParameters').validate().form()) {SetContentArea(GetHtmlDisplay('SaveParameters', 'Area', 'Controller'), $('#Parameters').serialize());} return false;"})%><%=Html.ResourceIcon("Save")%>
Here, we're saving a form and posting it to the server, but we disable inputs we don't want to validate if a checkbox is checked.
a bit of context
Please ignore the Html.Resource* bits, it's the resource management
helpers
The SetContentArea method wraps ajax calls, and GetHtmlDisplay
resolves url regarding an area,
controller and action
We've got combres installed that takes care of compressing, minifying
and serving third-parties libraries and what i've clearly identified as reusable javascript
My problem is that if somebody else defines a function DisableInputsForSubmit at another level (let's say the master page, or in another javascript file), problems may arise.
Lots of videos on the web (Resig on the design of jQuery, or Douglas Crockford for his talk at Google about the good parts of javascript) talk about using the namespaces in your libraries/frameworks.
So far so good, but in this case, it looks a bit overkill. What is the recommended way to go? Should i:
Create a whole framework inside a namespace, and reference it globally in the application? Looks like a lot of work for something so tiny as this method
Create a skeleton framework, and use local javascript in my views/partials, eventually promoting parts of the inline javascript to framework status, depending on the usage we have? In this case, how can i cleanly isolate the inline javascript from other views/partials?
Don't worry and rely on UI testing to catch the problem if it ever happens?
As a matter of fact, i think that even the JS code i've written that is in a separate file will benefit from your answers :)
As a matter of safety/best practice, you should always use the module pattern. If you also use event handlers rather than shoving javascript into the onclick attribute, you don't have to worry about naming conflicts and your js is easier to read:
<script type="text/javascript">
(function() {
// your button selector may be different
$("input[type='submit'].button").click(function(ev) {
DisableInputsForSubmit();
if ($('#EditParameters').validate().form()) {
SetContentArea(GetHtmlDisplay('SaveParameters', 'Area','Controller'), $('#Parameters').serialize());
}
ev.preventDefault();
});
function DisableInputsForSubmit() {
if ($('#IsDisabled').is(':checked')) {
$('#Parameters :input').attr('disabled', true);
} else {
$('#Parameters :input').removeAttr('disabled');
}
}
})();
</script>
This is trivially easy to extract into an external file if you decide to.
Edit in response to comment:
To make a function re-usable, I would just use a namespace, yes. Something like this:
(function() {
MyNS = MyNS || {};
MyNS.DisableInputsForSubmit = function() {
//yada yada
}
})();
what is the best way to create MVC architecture in jQuery?
Should I use jQuery.extend()?
jQuery.extend({
View: function(){}
});
...or jQuery Plugin?
(function($) {
$.fn.model = function() { return this; };
})(jQuery);
...or just objects in JavaScript?
var model = {}
var view = {}
var controller = {}
Thank you!
Just use objects in javascript. The view can contain all the knowledge of things like jquery and other UI concerns, while the controller/model can deal with other logic and communication with the server (assuming ajax). I wrote a blog post about this:
MVC Pattern with Javascript
Here is a great approach using jQuery.extend: http://welcome.totheinter.net/tutorials/model-view-controller-in-jquery/