Add TypeScript and tsconfig.json

[jtpio]

Fixes #809

Opening early so we can multiple passes on this if needed to gradually add typings.

TODO

• Add typescript and tsconfig.json
• Rename files to .ts
• Add typings
• Fix ESLint warnings
• Remove allowJs in tsconfig.json

[jtpio]

cc @JohanMabille since you were also interested in looking into this.

This is the first step to move to TypeScript, and there are still quite a few any to fix (here or in follow-up PRs).

[jtpio]

Another follow-up task would be to try updating to more recent packages.

[JohanMabille]

Thanks for pinging me @jtpio I have been swamped with other tasks and could not start this one :s

[SylvainCorlay]

@jtpio should we get this in?

[jtpio]

Sure.

As mentioned above this might need one more pass, but can be iterated on in follow-up PRs.

[SylvainCorlay]

Thanks!

I am looking at something that may conflict with this so, merging now!