BundleTransformer.Csso contains one minifier-adapter for minification of CSS code - KryzhanovskyCssMinifier. KryzhanovskyCssMinifier is based on the Sergey Kryzhanovsky's CSSO (CSS Optimizer) version 3.2.0.

As a JS engine is used the JavaScript Engine Switcher library. For correct working of this module, you need to install one of the following NuGet packages:

• JavaScriptEngineSwitcher.ChakraCore
• JavaScriptEngineSwitcher.Jint
• JavaScriptEngineSwitcher.Msie (only in the Chakra modes)
• JavaScriptEngineSwitcher.V8

After package is installed and JS engine is registered, need set a name of JS engine (for example, MsieJsEngine) to the name attribute of /configuration/bundleTransformer/csso/jsEngine configuration element in the Web.config file.

To make KryzhanovskyCssMinifier is the default CSS minifier, you need to make changes to the Web.config file. In the defaultMinifier attribute of the /configuration/bundleTransformer/core/css element must be set value equal to KryzhanovskyCssMinifier.