AFAIK, in Meteor, when compiling app, all javascript files and all css files will be merged to one file. I think this behavior will slow down app (because user must download all css and javascript that unnecessary for that page). Moreover, this behavior makes our app not dynamic, because maybe some page, we need different css or javascript files.
So my question is: How can we choose custom javascript and custom css for a template ? Does Meteor support this ?
Thanks :)
AFAIK Meteor is not supporting this exactly in that way. So you are left with two workarounds. One would be writing a own extension which helps you in that regard or finding one which already exists. And the other would be putting your special resources somewhere in the /yourMeteorApp/public folder which is excluded from the merge process (see http://docs.meteor.com/#/full/structuringyourapp). And now you could write some template specific logic to load and evaluate JS and CSS resources from there when your template is accessed. Resources in public are available directly on root level - so public/js/my.js would be available under www.example.com/js/my.js.
UPDATE:
This answer is quite old and in modern Meteor apps you should make use of the import logic (and the imports folder) which didn't exist in that way when I originally answered this: https://guide.meteor.com/structure.html#intro-to-import-export
This should be the best way to handle any dynamic JS requirements and strucutre an app by far nowadays.
In practice this has yet to be a problem for me. The combined javascript files are minified and obfuscated. The fact that any "page load" within the UI is done without a server GET makes the UI quite snappy. I have over 20 packages which add up to 2.1MB of js loading when the app cold-starts. Even on iOS it feels fast.
Related
Resently I have created an PhoneGap app.
Now I want to make more Efficient as it is very slow.
So I am searching on google & SO that minify version is make more faster then regualar .js file
also according tho this.
css best practices - combining all css into a single stylesheet?
keeping everything on file is good thing from fatching file from server but as in Phonegap app everything is at client side.
now my Questions are
1) does minify improves notable performance?
2) is it good Practice to make diffenet .js file or put everything on same is good one?
For your two questions my answer is quite similar.
2) Yes is always a good practice to write javascript in a different file as when you include that the file in you page almost every browser provides you the caching.
For the first time broswer looks into the cache and download the .js file from the server and store in its cache.
When again the same file is included it wil not download the js file but will refer to the cache.
This surely improves the performance.
1) As I explained above for the first time evrey js file gets download to client side. Now if you minify the js the download size will be very less hence will improve you performance. But it doesnt mean that you javascript code will start performing faster when you minify the js file.
Both the cases will improve the performance in some manner.
yeah you are right that why one should create a minify verstion of script if everything is going to run on client side , but in my experience there are two main benifits :
-One is while creating minify version , the compiler guides you about best practices and creates warning where required ( sencha cmd does).
-Other point is your app does reduce in size.
-You can have clean production version of your app.
Thanks
Here's some alternative approach to it.
Basically minifying and deferred loading of JavaScript files is a good practice. However, you can also consider trying native UI widgets on your apps to render the page much faster.
I am using Monaca for a while and found its native component very efficient and high performance. It's open-source as well. Take a look at the API reference.
The alternative solution is to use Steroids. It is closed-source, but it provides similar functions and components.
I like keeping myself busy building modular web-applications, but don't want to spend time where I can save some..
For example I'm building a news module that should be easily implemented over multiple sites, because the same web-application is used.
However not all websites will need a news module. Is it better/easier/faster to create an inline stylesheet/javascript file built into the module itself, than to create a big external stylesheet/javascript with all the libraries? Even though the file for the news module is not needed on all other webpages?
It seems to be much easier to create an inline library in the module itself. So that this only gets loaded when needed, and saves load time and bandwidth on the other pages.
The other thing is that I like writing 'plug-and-play' modules. Say I move a file across the file server into the module folder, and the application will take care of the rest. With inline sheets, I dont have to add new lines to the header/footer etc.
What is the best solution for this? When also taking into account that I rather spend 10 minutes moving a file and it works, than to spend 1 hour appending external libraries just because its more of a 'good practice'?
If you re building web applications, are you using the MVC patern? Do you separate your concerns? (your Templates/Views, your Models, and your logic(Controllers))
If you follow MVC, it makes easier maintaining and customizing your app.
To answer to your exact question, what you need is RequireJS. This way you have only one place to declare your requirements, and RequireJS will handle the rest.. Load order and more..
Quoting from the requirejs website:
Over time, if you start to create more modular code that needs to be
reused in a few places, the module format for RequireJS makes it easy
to write encapsulated code that can be loaded on the fly.
Inline is never a solid way to maintain CSS. Take care to separate the description of your layout from your views. You can easily include the file in the same directory as the module so it should not be an issue.
Or if you want just to load "on fly" some script you can use jQuery.getScript , http://api.jquery.com/jQuery.getScript/ . Otherwise you should follow George's way.
We have a large web project, where we need components which can talk to each other which can be put in a central repository of components for different projects.
Using reuirejs and Backbone for the modular development. Went through different boilerplate available for backbone and requirejs, but none matched my requirement. So I have created following directory structure. It can be explained as follows.
---resources
|---custom-components
|---mycomponent
|---js
|---views
|---models
|---collections
|---css
|---templates
|---mycomponent.js
|---mycomponent2
|---js
|---views
|---models
|---collections
|---css
|---templates
|---mycomponent2.js
|---libraries
|---backbone
|---underscore
|---jquery
|---jquery-ui
|---jqueryplugins
|---jcarouselite
|---thirdpartyplugins
|---page-js
|---mypage.js
|---mypage2.js
resources directory will contain all the resources. Under that we will have 4 directories as mentioned.
libraries, jqueryplugins and thirdpartyplugins are obviusly the directories for the name they say.
page-js directory will contain the actual main-js which will be used inside our html file as requirejs data-main attribute.
Custom-component is where all widgets created by us will reside, as you can see it has a js file with same name as that of the component, which will be entry point of this widget. This directory also has directories for js, css and templates. CSS and templates will be loaded by text plugin and CSS plugin respectively. Js directory will contain all the backbone code to make this widget work.
Custom components will be asked by main-js residing in page-js.
Coming to what I need.
1. I want experts to have review this directory structure in perspective of large web projects, where you will need to share your widgets with other teams. suggestions are welcome.
2. My each custom-component will define a module, which will have dependencies within package structure as well as outside package structure. I want to know, if there is any way to use r.js to optimize only my custom widget dependency within package structure and let the plugins and libraries optimized separately.
3. I am developing single page ajax application, so I will be asking modules on demand so I need to cleanup modules and widgets when I dont need them, is there any way for cleaning up I should be aware of?
About the directory structure
As a directory structure pattern, I highly recommend using directory structure of cakePHP. it's really robust as in words!! I'm running multiple apps (one of them is as big as Groupon) and it works just like a charm.
You may need to tweak it a little because, you know, cake is a PHP framework and yours is a javascript one.
Here is the cake's awesome MVC directory structure:
Please note that you may host thousands of apps on a single cake installation. so if you're interested, what are you waiting for? go to their site and read their docs.
About the cleaning up techniques
Well, here is one of the downsides of the Javascript which I don't like. there is no real way to destroy a OO module like in Java or C++. here we don't have such things like C++'s ~ destructors.
For many years, programmers use module = null to free up memory from un-used codes.
Take a look at these also:
Can dynamically loaded JavaScript be unloaded?
Loading/unloading Javascript dynamically
How to unload a javascript from an html?
Hope it helps and good luck on designing your app ;D
Probably I'm late in answering this, but anyway let me share my views here, incase someone else finds it useful.
Your directory structure looks alright. It is always a better design to keep your business components self contained in to a particular directory. I will not recommend Cake MVC structure which break the Open Close Principle. Also have a look at the directory structure recommended by http://boilerplatejs.org which is a reference architecture for large scale JavaScript development.
I do not get the question very clear. when r.js is run it will optimize all JS files it find in the directory (exclude possible) and then create a single script by going though the dependency tree. In production you only need that single script (plus locale files if i18n plugin is used)
Read my blog post below. It might give you some hints: http://blog.hasith.net/2012/11/how-much-multi-page-single-page.html
In my project each page has a bunch of dependent Javascript and Css. Whilst developing I just dumped this code right into the page but now I'm looking to clean it up...
it appears that the general approach out there is to package all the Javascript/CSS for an application into two big files that get minimised.
This approach has the benefit that it reduces bandwidth since all the front-end code gets pulled in just once from the server... however, I'm concerned I will be increasing the memory footprint of the application by defining a whole ton of functions for each page that I don't actually need - which is why I had them on a per-page basis to begin with.
is that something anyone else cares about or is there some way to manage this issue?
yes, I have thought of doing conditional function creation since I need to run code conditionally for each page anyway - though that starts to get a bit hackish in my view.
also, is there much cost to defining a whole ton of Css that is never used?
Serving the javascript/CSS in one big hit for the application, allows the browser to cache all it needs for all your pages. If the standard use case for your site is that users will stay and navigate around for a while then this is a good option to use.
If, however, you wish your landing page to load quickly, since there is a chance that the user will navigate away, consider only serving the CSS/javascript required for this page.
In terms of a performance overhead of a large CSS file - there will be none that is noticeable. All modern browsers are highly optimised for applying styles.
As for your javascript - try not to use conditional function creation, conditional namespace creation is acceptable and required, but your functions should be declared only in one place.
The biggest thing you can do for bandwidth is make sure your server is compressing output. Any static document type should be compressed (html, js, css, etc.).
For instance the jQuery Core goes from approx. 90KB to 30KB only because of the compressed output the server is sending to browsers.
If you take into account the compression, then you have to create some mammoth custom JS includes to really need to split-up your JS files.
I really like minifying and obfuscating my code because I can put my documentation right into the un-minified version and then the minification process removes all the comments for the production environment.
One approach would be to have all the shared javascript minified and compressed into one file and served out on each page. Then the page-specific javascript can be compressed/minified to its own files (although I would consider putting any very common page's javascript into the main javascript file).
I've always been in the habit of compressing/minifying all of the CSS into one file, rather than separate files for each page. This is because some of the page-specific files can be very small, and ideally we share as much css across the site as possible.
Like Jasper mentioned the most important thing would be to make sure that your sever is GZIPing the static resources (such as javascript and css).
If you have a lot of javascript code you can take a look on asynchronous loading of js files.
Some large project like ExtJs or Qooxdoo have build in loaders to load only required code, but here is a lot of libs which simplify this, and you can use in your project (e.g. head.js, LAB.js).
Thanks to them you can build application which loads only necessary files, not whole javascript code which in case of big apps can be a heavy stuff for browser.
some time ago, I was reading an article(a library built by some guy) about how his library can do
lazy loading of JS
resolve dependencies between JS
(typically encountered when trying
to "include" one js from another)
include files only once. thought
specified multiple times regardless
of how they are called (either
directly specifying it as file or
specifying it as one of the
dependencies)
I forgot to bookmark it, what a mistake. Can some one point me to something which can do the above. I know DOJO and YUI library have something like this, but I am looking for something which I can use with jQuery
I am probably looking for one more feature as well.
My site has asp.net user controls
(reusable server side code snippets)
which have some JS. Some of them get
fired right away, when the page is
loading which gives a bad user
experience. Yahoo performance
guidelines specify that JS should
be at the bottom of the page, but
this is not possible in my case as
this would require me to separate the
JS and the corresponding server side
control into different files and
maintenance would be difficult. I
definitely can put a jQuery
document.ready() in my user control
JS to make sure that it fires only
after the DOM has loaded, but I am
looking for a simpler solution.
Is there anyway that I could say "begin executing any JS only after DOM has loaded" in a global way than just writing "document.ready" within every user control ?
Microsoft Research proposed a new tool called DOLOTO. It can take care of rewriting & function splitting and enable the on-demand js loading possible.
From the site..
Doloto is a system that analyzes
application workloads and
automatically performs code splitting
of existing large Web 2.0
applications. After being processed by
Doloto, an application will initially
transfer only the portion of code
necessary for application
initialization. The rest of the
application's code is replaced by
short stubs -- their actual function
code is transferred lazily in the
background or, at the latest,
on-demand on first execution.
OK I guess I found the link
[>10 years ago; now they are all broken]
http://ajaxian.com/archives/usingjs-manage-javascript-dependencies
http://www.jondavis.net/techblog/post/2008/04/Javascript-Introducing-Using-%28js%29.aspx
I also found one more, for folks who are interested in lazy loading/dynamic js dependency resolution
http://jsload.net/
About the lazy-loading scripts thingy, most libraries just adds a <script> element inside the HTML pointing to the JS file to be "included" (assynchronously), while others like DOJO, fetches it's dependencies using a XMLHttpRequest and then eval's its contents, making it work synchronously.
I've used the YUI-Loader that is pretty much simple to use and you don't need the whole library to get it working. There are other libraries that gives you just this specific funcionality, but I think YUI's is the safe choice.
About your last question, I don't think there's something like that. You would have to do it yourself, but it would be similar to using document.ready.
i did in my framework a similar thing:
i created a include_js(file); that include the js file only if it isn't included reading and executing it with a synchronous ajax call.
Simply put that code in top of the page that needs dependencies and you're done!