`colorSchemes` calculation slows down initial load

[manuelpuyol]

Primer React parses color schemes on runtime using a reduce on a pretty big object:

react/packages/react/src/theme.ts

Lines 64 to 76 in 32b0cf7

	const colorSchemes: Record<Scheme, SchemeValue> = Object.entries(colors).reduce(
	(acc, [name, variables]) => {
	const {colors, shadows} = partitionColors(variables)
	return {
	...acc,
	[name]: {
	colors: omitScale(colors),
	shadows: omitScale(shadows),
	},
	}
	},
	{} as Record<Scheme, SchemeValue>,
	)

This is run whenever Primer is loaded in a JS bundle, which means that clients will have to run this expensive calculation before even starting to render anything.

Primer could pre-compile colorSchemes and include it in the bundle instead of having clients calculating it :)

I wrote two scripts comparing load times between the two methods here https://gist.github.com/manuelpuyol/f0b3c140c579e195374b30f25d5da833

In my tests, the load times went from ~15ms to <1ms!