dillon1000/react

Resolve host configs at build time (#12792)

* Extract base Jest config

This makes it easier to change the source config without affecting the build test config.

* Statically import the host config

This changes react-reconciler to import HostConfig instead of getting it through a function argument.

Rather than start with packages like ReactDOM that want to inline it, I started with React Noop and ensured that *custom* renderers using react-reconciler package still work. To do this, I'm making HostConfig module in the reconciler look at a global variable by default (which, in case of the react-reconciler npm package, ends up being the host config argument in the top-level scope).

This is still very broken.

* Add scaffolding for importing an inlined renderer

* Fix the build

* ES exports for renderer methods

* ES modules for host configs

* Remove closures from the reconciler

* Check each renderer's config with Flow

* Fix uncovered Flow issue

We know nextHydratableInstance doesn't get mutated inside this function, but Flow doesn't so it thinks it may be null.
Help Flow.

* Prettier

* Get rid of enable*Reconciler flags

They are not as useful anymore because for almost all cases (except third party renderers) we *know* whether it supports mutation or persistence.

This refactoring means react-reconciler and react-reconciler/persistent third-party packages now ship the same thing.
Not ideal, but this seems worth how simpler the code becomes. We can later look into addressing it by having a single toggle instead.

* Prettier again

* Fix Flow config creation issue

* Fix imprecise Flow typing

* Revert accidental changes