Why I'm Not Using Bundling In MVC4.. Yet
Last time I a posted
some initial info about Bundling and Minification abilities of MVC4. In
this post, I describe some concerns that prevents me of using it right
now. Let me remind that I'm doing review of MVC 4 beta and I hope some
of those concern would not be actual at the time of release. This is
only personal considerations, you might not agree with everything here.
Maybe the 'contra-intuitive' is not
exact word that reflects my frustration. What I mean, it does not do
what you might expect by default. Remember I described two methods
RegisterTemplateBundles() and EnableDefaultBundles()? It was really
unclear to me what they do until I looked into code. Modern frameworks
tend to be as less surprise as possible, but not in case of System.Web.Optimizations.
Development and production mode
The fact it does not take
into account 'Debug' and 'Release' mode is also very confusing. As same
as in point above, I have a different expectations how it should
behave. For 'Debug' mode it simply should do nothing - no optimization,
no compression. For release mode it should do as much as possible to
minify the number of HTTP request. It turns out that you have to create
some code on your own to make it happen.
Bundling is bad during debugging
While you in development
mode you do debug, no surprise here. Having FireBug or Chrome
any file and place breakpoint inside.
It is no so easy with bundling, cause it will package all your files
in one big chunk, so you need to open and find right place there. Since
the total number of line could be huge there, it's turns to be big deal.
As a workaround you have to have a copies of references, one you using on development and ones you use on production.
It's not well ironed
Since it's very young obviously it has some problems.
Be honest, I haven't seen on my own but one of the comments in my
previous post described the issue with minification of CSS files that
include -ie- specific selectors. That's probably not only one issue found.
What did I expect?
To do not have only critics I try to put some constructive part in post as well. Ok, so I see it should work to meet my needs?
First of all, it should be implemented as simple HTML razor
helpers. You just specify the name of bundle there, like "scripts/js"
and that's it. Helper is smart enough to understand what is active
environment at the moment. In case of 'Debug' it expanded to a bunch of
script references or links, for JS and CSS respectively. In 'Release'
mode it's indeed refers the bundle, so it's packaged and minified for
You might say, that 1. this is out of scope for System.Web.Optimization
framework 2. you can create this behavior easily on your own. This is
right, but in the same time if you deal with ASP.NET MVC4 you have some
expectation that is should work right and you are not forced to invent
the wheel again, so you have kind of consistency between numerous