Clarify Vaadin config parameters vs Vaadin modes

[mshabarov]

Tell us about your request

Vaadin can operate in different modes and exposes a lot of configuration parameters.
Despite the modes and parameters are already described, it's sometimes not clear or problematic:

• for which mode/configuration a particular parameter is valid (dev or prod mode, pre-compiled bundles or hot-deploy with Vite, routing with react or with vaadin router), or is it valid for all possible modes of running and configuring an application.
• which parameter could fix what problem, e.g. when one would need to force the prod bundle or disable bundle optimisation.

We may want to have:

• a kind of mapping / table that could list all relevant parameters per mode.
• troubleshooting / FAQ article that recommends a parameter value change vs an example of possible problem.

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[jcgueriaud1]

There are so many different configurations for the bundle that is really hard to debug it easily.

• dev mode:
  • frontend hotdeploy true/false
  • default dev bundle
  • built dev bundle
  • optimizeBundle ?
• production mode:
  • forceProductionBuild
  • optimizeBundle
  • LoadDependenciesOnStartup

One example in the documentation: devmode.optimizeBundle

Optimizes frontend resource bundles. All frontend resources in the classpath are included by default in the generated bundle in development mode. When set to true, the frontend build creates an optimized bundle by including only frontend resources that are used from the application entry points. It uses bytecode scanning, which increases application start-up time. Set to false to skip the optimization in production mode.

Set to false to skip the optimization in production mode

is confusing

Maybe we should guide our users about when to use it or a troubleshooting guide.

For example, in the troubleshooting guide we could have:
Missing component in production then you should probably check this parameter LoadDependenciesOnStartup.