By Scott Addie and David Pine
This article explains the benefits of applying bundling and minification, including how these features can be used with ASP.NET Core web apps.
What is bundling and minification
Bundling and minification are two distinct performance optimizations you can apply in a web app. Used together, bundling and minification improve performance by reducing the number of server requests and reducing the size of the requested static assets.
Bundling and minification primarily improve the first page request load time. Once a web page has been requested, the browser caches the static assets (JavaScript, CSS, and images). Consequently, bundling and minification don’t improve performance when requesting the same page, or pages, on the same site requesting the same assets. If the expires header isn’t set correctly on the assets and if bundling and minification isn’t used, the browser’s freshness heuristics mark the assets stale after a few days. Additionally, the browser requires a validation request for each asset. In this case, bundling and minification provide a performance improvement even after the first page request.
Bundling
Bundling combines multiple files into a single file. Bundling reduces the number of server requests that are necessary to render a web asset, such as a web page. You can create any number of individual bundles specifically for CSS, JavaScript, etc. Fewer files means fewer HTTP requests from the browser to the server or from the service providing your application. This results in improved first page load performance.
Minification
Minification removes unnecessary characters from code without altering functionality. The result is a significant size reduction in requested assets (such as CSS, images, and JavaScript files). Common side effects of minification include shortening variable names to one character and removing comments and unnecessary whitespace.
NerdNotes 