Split literal strings from base types

[johanneslumpe]

Properties like vertical-align allow literals but also the very wide string type. The issue with this is that TypeScript will widen the type to string, losing the ability to offer auto-completion hints for literal values and allowing any string value to pass type-checking. Would it be possible to define types which allow a very wide type like this:

type VerticalAlignPropertyBase<TLength> = Globals | TLength | "baseline" | "bottom" | "middle" | "sub" | "super" | "text-bottom" | "text-top" | "top";
type VerticalAlignProperty<TLength> = VerticalAlignPropertyBase<TLength> | string;

Auto-completion without split-out types

Auto-completion with split-out types

It's possible that I'm missing an obvious way to remove string from the union and be left only with the literal types and Globals/TLength, but so far I've been unlucky with my attempts.

[johanneslumpe]

Just realized that this is basically the same solution proposed in #8 (comment)

[frenic]

Closing if favor of #74