Rewrite in TypeScript

[happy5214]

As a long-range goal, we should try to integrate Babel so we can rewrite some of the more verbose code using more modern ECMAScript idioms and syntax. This should help with the Code Climate score.

[happy5214]

The esbuild integration supplants the Babel requirement. This is now a tracking bug.

[VisLab]

@happy5214 not sure what this is. Do we still need this since version 5 will switch to typescript?

[happy5214]

This has been refocused to TypeScript and targeted for v5.0.0.