Error running .Net application after upgrading .Net NuGet 3.0.91 to 3.0.97

[jsmitch122]

In existing code with method WebOptimizer.IAssetPipeline.AddScssBundle(.... we now get the following error when running.

System.InvalidOperationException: JS engine is not registered.
at Microsoft.Extensions.DependencyInjection.PipelineExtensions.CheckJsEngineRegistration()
at Microsoft.Extensions.DependencyInjection.PipelineExtensions.AddScssBundle(IAssetPipeline pipeline, WebOptimizerScssOptions options, String route, String[] sourceFiles)

[Taritsyn]

Hello!

Since the original library is written in JavaScript, you will need a JS engine to run it. As a JS engine is used the JavaScript Engine Switcher library. First of all, you need to install the JavaScriptEngineSwitcher.Extensions.MsDependencyInjection package which makes registration of JS engines more convenient. Then you need to install one of the NuGet packages containing a JS engine provider:

• JavaScriptEngineSwitcher.ChakraCore
• JavaScriptEngineSwitcher.Jint
• JavaScriptEngineSwitcher.Msie (only in the Chakra “Edge” JsRT mode)
• JavaScriptEngineSwitcher.V8

After installing the packages, you will need to register the default JS engine.

[Taritsyn]

Hello, Peter!

Previously, this library was tightly bound to the JavaScriptEngineSwitcher.V8 module. Now you independently determine which module to use (see the “Making used JavaScript engine configurable” issue).

Maybe there should be a default JS engine included still, with the ability to replace it if desired? - just to avoid such upgrade exceptions; most would probably expect consistent behaviour during package upgrades.

[Taritsyn]

Default engine is an additional dependency, and not the most lightweight one. Nowadays it is better to avoid additional dependencies.

It is possible that in this case the major version should have been changed.