How to organize JS functions using objects - javascript

I would like to know if organizing JS functions in object notation is a good or bad practice. The intention is to keep js organized/easy to maintain.
Example:
var helper = {
myAlert: function(){
return alert('Alert from helper');
},
toLowerCase: function(){
var str = document.getElementById("txt").innerHTML;
return alert(str.toLowerCase());
}
}
Html:
<body>
<h1 onclick="helper.myAlert()">Hello Plunker!</h1>
<p id="txt" onclick="helper.toLowerCase()">Testing LowerCaseFunction</p>
</body>
Plunker
Thanks in advance!!!

code organization is an strategic topic when it comes to make software survive more than a couple of years yet this is also a very opinionated terrain.
You can make a nice job by keeping semantically related functions near each other under the same namespace, or even make it related to the user story being solved, it can be done in many ways.
If you want to know this approach is good enough, simulate an iteration on it, add a new feature and see what happens to the code.
The code avoids duplication? It gets reusable? Is it easy to locate and relate with the user needs? If so, then it will help you.
Finally, if applicable consider to use some module builder, webpack or browserify for example, so you will be able to not only separate your modules logically but "physically" too.

For me it is a good practice. When working with little projects, you do do see it important, but in large projects you are almost obliged to do it.
simply imagine you are making a chat website, you will need to create function that will delete messages, add messages. you can simply do it as you did it up.
var messages = {
remove:function{//remove code},
add:function{//add code}
}
in this way you can define contacts management object as
var contacts = {
remove:function{//remove code},
add:function{ //add code},
block:function{//block code}
}

This isn't really an answer per se but too long for a comment:
Since you are asking about best practices I'd like to point out a few things in your sample:
onclick. Just...don't. You don't want to grep through your JS trying to diagnose a behavioral problem only to realize 8 hrs in that its being called from HTML. That's a maintenance nightmare waiting to happen.
innerHTML again, just...don't. Unless you are working with HTML. 9 times out of 10, textContent will do and you can assign to it without security risk. Google 'innerHTML security risk' for more info.
alert alert blocks. Blocks your whole browser until you click annoying box. And which of your 50 open tabs was it in? Blocking is bad. Use console.log. You're a dev, and you do have devtools open right?
Your toLowerCase function. You mix data access (getting the DOM element's text) with data transformation. Bad idea.
Note that none of these are particular to JavaScript, they apply to pretty much all UI coding: don't mix business logic with the presentation layer, don't block user interactions, use the principle of least privilege, don't mix data access with data processing, etc. And all of the above issues are bigger problems than whether or not you namespace some functions.

Related

Few basic jQuery concepts (splitting code into files, settings storage, modular systems)

Right now I'm writing a small jQuery plugin for fun and profit, so since I'm not too familiar with this library, there's a few questions made me confused at this point.
Let's say we have a pretty simple plugin:
(function($) {
onButtonPress() {
console.log('Button pressed!');
}
render(container, settings) {
$(container).addClass(settings.boxClass);
$('<button></button>').appendTo(container).addClass(settings.addImageButton).on('click', onButtonPress);
}
$.fn.myAwesomeForm = function(options){
var settings = $.extend({
'boxClass': 'box-header with-border',
'addImageButton': 'btn btn-primary btn-sm',
}, options);
render(this, settings);
}
}(jQuery));
1) Let's imagine our render() method is implemented using 25 different functions and they are 400 total lines of code long. Some of these functions are responsible for drawing the UI, some of them doing ajax queries, some of them is just some helpful snippets I made to reduce the amounts (and the ugly-ness) of the code.
How I could split this code into separate files? As far as I understand, I need to write code in different files, then use a tool like grunt/gulp to create a task or watcher to merge them all into a single *.js file (and probably provide a minified version as well), but right now I'm a bit confused about how I should do that. Is there any kind of 'best practice' thing, or any common approach to such thing to make sure that my code will be less confusing for the other possible maintainers?
2) Let's say that default settings is an array of 70 [probably nested] elements, and I want to access one of them in onButtonPress function. Oh, also different one I want to access in someOther function, and there's a few I need for deleteForm() function, so generally it would be better for my code if settings array will be something I could access from pretty much every place of the code, and most important thing, I could have 5-6 instances of my form on the page, so I cannot use a local-scope variable in plugin file for that.
I read about the approach of saving settings in the data fields, but it feels a bit weird for me to be frank. Is there's any better way I could implement it?
3) Let's say that my plugin is growing, and now I want to add a few more pre-defined settings for Bootstrap and Sematic UI frameworks adding to AdminLTE I use now.
Of course, generally I want my $('#form').myAwesomeForm({}) call to not be 70-lines long, so generally I'm looking for a way to somehow move the default settings in another file, to say "myplugin-defaults-lte.js", so then I could do something like this:
<script type='text/javascript' src="myplugin-defaults-bootstrap.min.js">
<script type='text/javascript' src="myplugin.min.js">
<script type='text/javascript'>
// Here's my form. Already bootstrap-customized.
$('#form').myAwesomeForm();
</script>
I'm not sure if it's the best pattern, but perhaps you got the idea. So generally, can anyone please provide a simple code snippet, or something like this, because at this point things starting to be confusing as hell to me, so I'm really not sure how to approach it correct way?

What are the arguments against the inclusion of server side scripting in JavaScript code blocks?

I've been arguing for some time against embedding server-side tags in JavaScript code, but was put on the spot today by a developer who seemed unconvinced
The code in question was a legacy ASP application, although this is largely unimportant as it could equally apply to ASP.NET or PHP (for example).
The example in question revolved around the use of a constant that they had defined in ServerSide code.
'VB
Const MY_CONST: MY_CONST = 1
If sMyVbVar = MY_CONST Then
'Do Something
End If
//JavaScript
if (sMyJsVar === "<%= MY_CONST%>"){
//DoSomething
}
My standard arguments against this are:
Script injection: The server-side tag could include code that can break the JavaScript code
Unit testing. Harder to isolate units of code for testing
Code Separation : We should keep web page technologies apart as much as possible.
The reason for doing this was so that the developer did not have to define the constant in two places. They reasoned that as it was a value that they controlled, that it wasn't subject to script injection. This reduced my justification for (1) to "We're trying to keep the standards simple, and defining exception cases would confuse people"
The unit testing and code separation arguments did not hold water either, as the page itself was a horrible amalgam of HTML, JavaScript, ASP.NET, CSS, XML....you name it, it was there. No code that was every going to be included in this page could possibly be unit tested.
So I found myself feeling like a bit of a pedant insisting that the code was changed, given the circumstances.
Are there any further arguments that might support my reasoning, or am I, in fact being a bit pedantic in this insistence?
Script injection: The server-side tag could include code that can break the JavaScript code
So write the code properly and make sure that values are correctly escaped when introduced into the JavaScript context. If your framework doesn't include a JavaScript "quoter" tool (hint: the JSON support is probably all you need), write one.
Unit testing. Harder to isolate units of code for testing
This is a good point, but if it's necessary for the server to drop things into the page for code to use, then it's necessary. I mean, there are times when this simply has to be done. A good way to do it is for the page to contain some sort of minimal block of data. Thus the server-munged JavaScript on the page really isn't "code" to be tested, it's just data. The real client code included from .js files can find the data and use it.
Thus, the page may contain:
<script>
(function(window) {
window['pageData'] = {
companyName: '<%= company.name %>',
// etc
};
})(this);
</script>
Now your nicely-encapsulated pure JavaScript code in ".js" files just has to check for window.pageData, and it's good to go.
Code Separation : We should keep web page technologies apart as much as possible.
Agreed, but it's simply a fact that sometimes server-side data needs to drive client-side behavior. To create hidden DOM nodes solely for the purpose of storing data and satisfying your rules is itself a pretty ugly practice.
Coding rules and aesthetics are Good Things. However, one should be pragmatic and take everything in perspective. It's important to remember that the context of such rules is not always a Perfect Divine Creation, and in the case of HTML, CSS, and JavaScript I think that fact is glaringly clear. In such an imperfect environment, hard-line rules can force you into unnecessary work and code that's actually harder to maintain.
edit — oh here's something else I just thought of; sort-of a compromise. A "trick" popularized (in part) by the jQuery gang with their "micro template" facility (apologies to the web genius who actually hit upon this first) is to use <script> tags that are sort-of "neutered":
<script id='pageData' type='text/plain'>
{
'companyName': '<%= company.name %>',
'accountType': '<%= user.primaryAccount.type %>',
// etc
}
</script>
Now the browser itself will not even execute that script - the "type" attribute isn't something it understands as being code, so it just ignores it. However, browsers do make the content of such scripts available, so your code can find the script by "id" value and then, via some safe JSON library or a native browser API if available, parse the notation and extract what it needs. The values still have to be properly quoted etc, but you're somewhat safer from XSS holes because it's being parsed as JSON and not as "live" full-blown JavaScript.
The reason for doing this was so that the developer did not have to define the constant in two places.
To me, this is a better argument than any argument you can make against it. It is the DRY principle. And it greatly enhances code maintainability.
Every style guide/rule taken to extreme leads to an anti-pattern. In this case your insistence of separation of technology breaks the DRY principle and can potentially make code harder to maintain. Even DRY itself if taken to extreme can lead to an anti-pattern: softcoding.
Code maintainability is a fine balance. Style guides are there to help maintain that balance. But you have to know when those very guides help and when they themselves become a problem.
Note that in the example you have given the code would not break syntax hilighting or parsing (even stackoverflow hilights it correctly) so the IDE argument would not work since the IDE can still parse that code correctly.
it simply gets unreadable. You have to take a closer look to divide the different languages. If JavaScript and the mixed-in language use the same variable names, things are getting even worse. This is especially hard for people that have to look at others people code.
Many IDEs have problems with syntax highlighting of heavily mixed documents, which can lead to the loss of Auto-Completion, proper Syntax Highlighting and so on.
It makes the code less re-usable. Think of a JavaScript function that does a common task, like echoing an array of things. If you separate the JavaScript-logic from the data it's iterating over, you can use the same function all over your application, and changes to this function have to be done only once. If the data it's iterating over is mixed with the JavaScript output loop you probably end up repeating the JavaScript code just because the mixed in language has an additional if-statement before each loop.

What software/webapp can I use to edit HTML pages?

Ok, my question's not as broad as it seems, to summarize 8 months effort on my part:
I create chunks of re-usable, extensible XHTML which degrades gracefully and is all kinds of awesome. Most of my code chunks are provided a Javascript interaction layer, and are styled with CSS. I set to work pulling my code chunks into Dreamweaver as 'Snippets' but they're unintelligent chunks of text. Also, once inserted, my beautiful code chunks get mangled by the non-techies who are the ones actually using Dreamweaver.
Also, because they're unintelligent snippets, I have a line of Javascript which configures the code chunks when initialised - see this post for further detail on my approach. But currently I have to replicate a single code chunk as many times as there are configuration options (so each 'snippet' may only differ from another of the same type by ONE config value). This is incredibly lame, it works, but its lame and time-consuming for me to re-deploy a bunch of snippets and hard for my team to remember all the variations.
So I have a series of requirements, to my mind, as the most likely things to solve in any system I put my chunks into:
The inserted code is not modified at insertion time, by the system
The code to be inserted needs to allow config options
I'd be overjoyed if, once inserted, the only editable parts are text nodes
Copy and pasting these whole objects
A clean interface from which to choose from my range of code chunks
It's a serious list of requirements I presume, much searching led me to Kompoze and its 'Smart widgets' which, according to a random post from 2004, suggests XUL files can be created and extensions can be made which sounds vaguely like what I want. The text editor itself was less prone to destruction, when compared to Dreamweaver.
So yeah, I've chased too many rabbits on this one, keen as for a solution whether Software+extension, or Webapp.
EDIT:
Btw, it did occur to me to investigate a highly customised TinyMCE instance, but I don't know feasible that is, and unless there's some sweet backend available, I'm stuck with local editing of files for now - not even on a web server...
To my mind the best answer to this question will solve most of the above, and provide some general workflow advice alongside the suggestion(s).
I would go with a solution based around the excellent markItUp! editor. It's very simple to extend it to cope with the requirements you have. You can add sophisticated logic, and it's nice and shiny.
I'd probably combine it with Jeditable for the inline node editing, and build the whole thing on top of Django, for ease and convenience. Completely customisable, surprisingly easy to work with, portable and cross-platform, and easy to set-up for off-line use. Oh, and all free and open-source.
What do you think of this approach:
<div class="thing">
<elements... />
<script type="text/javascript">
document.write('<span id="thing' + thingNo + '"></span>')
new Thing().init({ id:'thing'+thingNo; });
thingNo += 1;
</script>
</div>
Of course, you'll have to change Thing().init so that it would initialize the parent (instead of current) node.
Have you considered server-side includes where the directive is either a generated page or a shell command? E.g.:
<!--#include virtual="./activePage.aspx?withParam1=something&param2=somethingelse" -->
or
<!--#exec cmd="shellCommand -withParams" -->
You can reuse the same page or command, and provide parameters specific to each usage in each XHTML page.

JavaScript messy code in large projects with jquery etc?

Calling the javascript gurus out there.
Basically my question is regarding how you structure your code, both visually and for functionality for example do you wrap everything in objects using this structure:
var myapp={
binds:function(){
//put some event listeners for jquery etc...
},
otherfunc:function(){
//do some other thing
},
init:function(){
//call myapp.binds and other functions and other stuff to intialize your app.
}
};
Then finally
$(document).ready(myapp.init);
The thing is with a structure like this I think JSLint complains doesn't it? Whats the pros and cons using a structure like this or is there a generally better way to structure your code? Do you follow a certain pattern from $(document).ready(call) to putting all your event listeners and "initializing" your app, do you use separate objects for methods and variables?
I also think "visually" if you have a very large webapp this structure eventually looks very messy, but maybe it's just me I don't know, any input is appreciated thanks.
Using Inheritance Patterns to Organize Large jQuery Applications
explain in detail and with better practice by Alex
http://alexsexton.com/?p=51
its very very well explain, must see
other links
How To Manage Large jQuery Apps 5 months ago
It doesn't matter much how you structure your code as long as you follow the essentials rules of programming that your teacher thought you:
Don't write repetitive code
A function must do 1 and only 1 thing
Document your code
Some other small things but mostly the above... oh and apply lots of common sense
The only error you get from that is "implied global." You can get rid of the warning for document by using this.document instead (since window is the context). The implied global for $ will stay unless you paste in the jQuery source (then gl with all the errors in that).
I trust JSLint--a lot. On big projects I tend to make object literals as you did above but I use a module pattern for object security:
var myapp = (function () {
var secret_stuff, public_stuff;
return {
stuff: public_stuff
}
}());

How do you organize your Javascript code?

When I first started with Javascript, I usually just put whatever I needed into functions and called them when I needed them. That was then.
Now, as I am building more and more complex web applications with Javascript; taking advantage of its more responsive user interaction, I am realizing that I need to make my code more readable - not only by me, but anyone who replaces me. Besides that, I would like the reduce the moments of 'what the heck, why did I do this' when I read my own code months later (yes, I am being honest here, I do have what the heck was I thinking moments myself, although I try to avoid such cases)
A couple weeks ago, I got into Joose, and so far, it has been good, but I am wondering what the rest do to make their chunk their codes into meaningful segments and readable by the next programmer.
Besides making it readable, what are your steps in making your HTML separated from your code logic? Say you need to create dynamic table rows with data. Do you include that in your Javascript code, appending the td element to the string or do you do anything else. I am looking for real world solutions and ideas, not some theoretical ideas posed by some expert.
So, in case you didnt't understand the above, do you use OOP practices. If you don't what do you use?
For really JS-heavy applications, you should try to mimic Java.
Have as little JS in your HTML as possible (preferably - just the call to the bootstrap function)
Break the code into logical units, keep them all in separate files
Use a script to concatenate/minify the files into a single bundle which you will serve as part of your app
Use JS namespaces to avoid cluttering up the global namespace:
var myapp = {};
myapp.FirstClass = function() { ... };
myapp.FirstClass.prototype.method = function() { ... };
myapp.SecondClass = function() { ... };
Using all these techniques together will yield a very manageable project, even if you are not using any frameworks.
I use unobtrusive javascript, so, outside of the script tags I don't keep any javascript in the html.
The two are completely separated.
A javascript function will start when the DOM tree is completed, which will go through the html and add the javascript events, and whatever else needs to be changed.
In order to organize, I tend to have some javascript files that are named similar to the html pages that they use, and then for common functions I tend to group them by what they do, and pick a name that explains that.
So, for example, if I have UI functions then I may call them: myapp_ui_functions.js
I try to put the name of the application in the filename, unless there is some javascript that is common to several projects, such as strings.js.
I have (usually) one file that contains a bunch of functions and that's it. That is included in every page that uses Javascript. In the pages themselves, I'll make the calls to the functions like:
$(function() {
$("#delete").click(delete_user);
$("#new").click(new_user);
});
where delete_user() and new_user() are defined in the external file.
I too use unobtrusive Javascript, which for me means jQuery (there are other libraries that are unobtrusive).
You don't want a separate file for each page. That just means more unnecessary external HTTP requests. With one file—assuming you've cached it effectively—it'll be downloaded once and that's it (until it changes).
If I have a large amount of Javascript or the site is effectively split into multiple areas then I may split the Javascript but that's not often the case.
Also, in terms of my source code, I may have multiple JS files but I'll often end up combining them into one download for the client (to reduce HTTP requests).
More at Multiple javascript/css files: best practices? and Supercharging Javascript in PHP.
I've been rewriting a lot of my reusable code as jQuery plugins. I moved to jQuery from Prototype when I started doing ASP.NET MVC. Overtime I've migrated a lot my reusable code, or at least the ideas, from Prototype-based OO to jQuery-style plugins. Most of these are stored in their own JS files (mainly intranet apps so page load speed is pretty high anyway despite the extra requests). I suppose I could add a build step that coalesces these if I needed to.
I've also settled on a MasterPage approach that uses a ContentPlaceHolder for scripts that is right before the closing body tag. The standard jQuery/jQuery UI loads, and any other common JS goes right before the script placeholder in the MasterPage. I have tiny bit of JS at the top of the MasterPage that defines an array that holds any functions that partial views need to run on page load. These functions are run from the base document.ready() function in the MasterPage.
All of my JS is completely separate from my mark up. Some JS may exist in partial views -- these are encapsulated when the partial may be included more than once to make it specific to that instance of the view -- but generally not. Typically only included in the placeholders so that it's loaded at the bottom of the page.
Also, if you want to go OO heavy, check out mochikit: http://www.mochikit.com/
I find that developing your javascript using OO methodology is the way to go if you want it to be clean, readable and even somewhat secure. I posted the following question
Cleanest format for writing javascript objects
And got some fantastic responses on how to write my javascript code well. If you follow these basic principles you can use almost any library, such as yui, jquery and prototype, with ease.

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