Generate: Support for frameworks other than Lit

[jogibear9988]

I've writte my own Base Element (https://github.com/node-projects/base-custom-webcomponent)

cause we liked the declarative Style more then the "render()" one from LIT.

Is it possible to also parse my elments? What do I need to do? I'd like that also the templates in my elements are parsed and slots and parts are extracted.
(i've already a few components who use it as a base: https://github.com/node-projects)

Also my designer uses it: https://node-projects.github.io/web-component-designer-demo/index.html

[bennypowers]

I think the way to go here is to dispatch to framework subpackages, based on detected package imports

e.g.

• ✔️ if import { LitElement } from 'lit' is detected, dispatch to the lit subpackage.
• ✔️ if import { BaseCustomWebComponentConstructorAppend, html } from '@node-projects/base-custom-webcomponent' is detected, dispatch to the baseCustomWebComponent subpackage

We are not trying to support the full dynamic range of possible javascript syntax or module architecture. We will consider it an end user error if they either

• ❌ remap those imports to another name i.e. import { LitElement } from '#my-alias-of-lit'
• ❌ import multiple frameworks into a single file i.e. import * from 'lit'; import * from 'lume' or whathaveyou

each framework's subpackage will have a common interface to the rest of the project, which is TBD but will be based on the existing functions.

We will not:

• ❌ expose a javascript plugin system
• ❌ expose the AST as a plugin API
• ❌ make parsing or matching a config concern

What do you think of that plan? The major downside is that every framework will be compiled in, but this project is already a monolith, by design.

[bennypowers]

cc @trusktr

see #108