Make download links cross-platform

[roryabraham]

Fixes

#287

Tests

1. Open the app on web, and verify that you see links for Desktop, iOS, and Android in the bottom of the left-hand-nav.
2. Open the app on desktop, and verify that you see links for Web, iOS, and Android in the bottom of the left-hand-nav.
3. Open the app on iOS, and verify that you see only one link in the bottom of the left-hand-nav that says "View on web" (added a couple words to fill space when it's the only link).

[sketchydroide]

I'll review once you have created the index.js for the desktop and web 😄

[roryabraham]

Okay, I've set this up so that we can use .desktop.js/.webify.js file extensions. It was impossible to use .web.js file extensions for our own web-specific code, because that file extension is already used by react-native-web, and Electron relies on react-native-web, so we couldn't exclude that file extension from the webpack build for desktop.

[roryabraham]

Had to update the eslintrc because it was complaining about a "missing file extension for import". Basically, without any plain .js files in the module, eslint was unsure about which files could be imported, so we just needed to add the list of javascript file extensions to the configuration.

[tgolen]

What is "webify" and could we make that just .web.js?

[marcaaron]

+1

[roryabraham]

Yeah, unfortunately we can't just use web.js, because it is already used by a number of files in react-native-web, and the desktop app needs those files. Therefore, we can't exclude .web.js files outright from the webpack build for the desktop app. So we have to just some other extension to denote web-specific implementation, hence: webify

[marcaaron]

What about .browser.js?

[tgolen]

Ah, OK. Yeah, I think browser or website would work

[roryabraham]

Do we like .browser.js or website.js?
I actually think I like website better, because Electron essentially is a sandboxed browser, of sorts.

[marcaaron]

+1

[roryabraham]

Okay, I've updated this PR to:

• Improve the README, and move to a separate section so that we can go into a bit more detail
• Add some code comments
• Use index.website.js instead of index.webify.js
• Use an array of regexes instead of regexUnion (I left the RegexUtils, because it is very general and could still be useful in the future)

[tgolen]

Thanks!