The Difference Between Minifying and Combining

In: Smart Tips
Jun 25, 2018

minify file sizesMinifying and combining are two of the core constructs of our performance plugin, SmartCache, and the Holy Grail of performance endeavors across the Internet.  Minifying and combining make up the first step on the path to optimizing a website, after which tasks such as cache control, image compressing, and content delivery are done.

But what does it mean to minify and combine and how does SmartCache do it better?

Minification is the work of reducing the size of downloaded files, typically text-based Javascript (instructions executed by your browser that add functionality and interactive features) and CSS stylesheets (a set of formats that determine how webpages are arranged and styled), by removing extraneous spaces, line-returns, and comments.  While these spaces improve readability for developers, software doesn’t need it.  Furthermore, every extra space and line-return adds bytes to the download.  And bigger files take longer to serve.

combine similar files togetherWhile shrinking files is advantageous, asking a browser to download many files required to render a webpage is a further source of slow performance.  That is because modern browsers and most Internet Service Providers limit the number of downloads to between 2 and 6 files at a time.  While a typical webpage today might include 100 or more individual files, at the pace of 6 simultaneous downloads, such a webpage could take many seconds to display and become fully operational.  Combining files, or the act of grouping multiple similar files together into larger ones, means that your browser will need to make fewer calls which results in a quicker display time.

When both minification and combination are employed webpage loading performance will improve by a discernible measure.  Making files smaller and grouping them in such a way that fewer overall files are transmitted will result in faster downloads.

So how does SmartCache’s version of minification and combination differ from the above established methods?  For the most part SmartCache follows this approach, but extends it by minifying the combined files as well, resulting in extremely small file footprints.

In many tests we have seen optimized reductions 51% or more versus the original content size and counts.  This is significant.  It’s like dehydrating half of the total accumulated size of the files requested by the webpage.  This has the potential of shaving seconds off of the download time.  Plus caches outside of the site, including in your browser and on CDNs, are smaller too.