Add babel plugin for preprocessing templates with ast transforms

[wondersloth]

In v2 addons there is no way to apply template transforms to components. This is common in addons that use ember-cli-preprocessor-registry and register transforms for modifying templates.

• Needs some documentation somewhere on how to use this in the sample-babel.config.json or in a sample-babel.config.js file.

[ef4]

Hi @wondersloth, thanks for tackling this.

This plugin does the same thing as babel-plugin-stage1-inline-hbs. So perhaps instead you could

• move that plugin into @embroider/shared-internals so it would be available both to @embroider/core and to @embroider/addon-dev.
• reexport it from @embroider/addon-dev (there is already an example of another plugin that works this way) so it's convenient for addon authors
• document how to use it from the sample babel config.

[ef4]

Oh, also be aware that there are two separate files related to that plugin:

• babel-plugin-stage1-inline-hbs.ts is the actual implementation, written in a way that isn't tied to any node APIs so it's portable to other environments
• babel-plugin-stage1-inline-hbs-node.ts is a wrapper around that for convenient usage from Node (it can load the ember template compiler from the filesystem, for example).

[wondersloth]

@ef4

I don't think I entirely understand your ask, and I want to clarify what you're suggestions are:

Move babel-plugin-stage1-inline-hbs.ts into @embroider/shared-internals

If I move this file into shared-internals:

• I need to hoist a TemplateCompiler type/interface.
• I need to have a compiler in addon-dev so that I can properly make() the babel-plugin-state1-inline-hbs plugin.

At this point I need to hoist more code from @embroider/core to @embroider/shared-internals to make that work across packages. FIles like template-compiler-common.ts, resolver.ts, babel-pluign-adjust-imports.ts

OR...

Refactor the pieces of template-transform-plugin.ts and babel-plugin-stage1-inline-hbs.ts to shared-internals

I suppose for this it's doable, just requires abstracting out the visitors?

[wondersloth]

Discussed concerns in Embroider Office Hours with @ef4

Moving babel-plugin-stage1-inline-hbs.ts to shared-internals will require many files to be hoisted to shared, which will cause a couple issues.

• It will gut @embroider/core of a lot of features.
• It will bloat @embroider/shared-internals which is consumed by ember-auto-imports.

Recommended path

• Refactor template-transform-plugin to depend on babel-plugin-stage1-inline-hbs.ts via @embroider/core.
• In @embroider/add-dev drop shared-internals as a dep.

[NullVoxPopuli]

Can this be rebased? looks like a lot of stuff from main is (for some reason) showing up in this PR's diff

[wondersloth]

@ef4 is there any additional work needed before merge?

[Kaceykaso]

@ef4 @wondersloth any chance we can get this merged today or tomorrow? Looking to announce internally ;)
Thanks a bunch!