[api change] Make additionalProperties a Record

[scoiatael]

Sorry I didn't make this work when introducing this feature, but I didn't know enough TypeScript. Anyhow, Record type is better here, since it makes checking keys much more efficient.

Also, a couple of additional quality-of-life-changes:

• expose AliKey as part of public API,
• expose additionalProperties on Group (things like ArtboardData are on Group, not Layer).

Let me know WDYT :)

[scoiatael]

@pastelmind @dlehdanakf WDYT? Looks like CI passes now. Should I assign one of you (which one) as a reviewer? :)

[pastelmind]

That is odd. Object.fromEntries() is available in Node 14 according to node.green. Maybe there is a problem with our ESLint or TypeScript config?

Edit: Looks like our browserslist config specifies minimum Node.js version as 12.0.0:

psd/package.json

Lines 19 to 25 in 5e1fd35

	"browserslist": [
	"chrome >= 57",
	"firefox >= 52",
	"safari >= 11",
	"edge >= 79",
	"node >= 12"
	],

Object.fromEntries() should be available in Node.js v12.0.0, according to MDN, this V8 blog article, and this tweet. So the compilerOptions.lib setting in our tsconfig.base.json does not quite accurately reflect the landscape of our targets.

But some of our browser targets do not support Object.fromEntries(), yet. To use it without a polyfill, we would have to bump our minimum supported browser version to higher values.

In summary, the Object.fromEntries() polyfill is a welcome addition, but not because of Node.js, but rather the browsers we intend to support.