Add FontFace component

[stevenbenisek]

:sparkles: Add FontFace resource :books: Document <FontFace \> and useFontFace :point_right: Add <FontFace /> example

Resolves #76

[stevenbenisek]

When reviewing especially keep an eye on:

• Typescript definitions (I'm by no means an expert, would love to get feedback)
• Error handling if the browser doesn't support window.FontFace (https://caniuse.com/#feat=font-loading). It throws a TypeError that can be caught by adding an error boundary (not sure if this is the right approach?).

[swyxio]

interesting use of suspense. why not offer url and format as props? just a random comment, obviously make the api however you like

[stevenbenisek]

No, it's absolutely a valid comment. In fact, I thought about url and format as props myself. The reason I didn't do it is because with source you can add a comma separated list of url and format pairs (like the CSS @font-face-rule); e.g.:

<FontFace
  family="Name"
  source="url(path/to/name.woff2) format('woff2'), url(path/to/name.woff) format('woff')" />

This is great to provide fallbacks if the preferred format is not supported or to refer to a local font as the primary option.

An alternative API could be using source as an array:

<FontFace
  family="Name"
  source={[
    {
      url: 'path/to/name.woff2',
      format: 'woff2',
    },
    {
      url: 'path/to/name.woff',
      format: 'woff',
    },
  ]}
/>

[swyxio]

hmm, yea i see. idk, you can also leave it as a string and ask for OSS to write validation regex :)

[stevenbenisek]

You do get limited runtime feedback. If you call window.FontFace with an invalid source it will throw a DOMException. You're not completely left in the blind. Might just stick with a string. The reason I opted for a string in the first place was because it aligns with the spec. It's also the same as the @font-face-rule so it's well known and well documented.