uber / nebula.gl / 1855 / 1

22%

master: 22%

push

travis-ci-com

Typescript migration (#377)

I created a new PR to take advantage of conversion tooling.
## Strategy
* use Flow to typescript CLI https://github.com/khan/flow-to-ts to automate most of the conversion
* Use of [Typescript ESLINT](https://github.com/typescript-eslint/typescript-eslint) to quickly fix types issues.
* Convert the code to typescript with minimal/no  refactor.
* use Loose typescript rules to allow progressive transition
    * I disabled `typescript strict mode`
   * Use `//@ts-ignore`  to mask types errors
   * Use `any` for unknown types

**This PR does not bring the code to the typescript standard.  My idea was to convert first to typescript and from there, we all can improve the types.**

While converting, a lot of errors, missing imports and export surfaced. I fixed the best I could.

## What is next?
The following tasks can be done to improve code quality
- Converting examples to typescript or remove types from examples.
- Move to a stricter typescript and ESLINT rules
- Replace `geojson-types.ts` by [@types/geojson](https://www.npmjs.com/package/@types/geojson)
## Note
If this PR is merged, please take 10 min to get familiar with [Typescript](https://www.typescriptlang.org)

To create a file that has `jsx` please use `.tsx` extension. For anything else use `.ts`.
I upgraded to prettier 2.0 which seems to now have trailing commas by default.

489 of 2398 branches covered (20.39%)

Branch coverage included in aggregate %.

1168 of 4974 relevant lines covered (23.48%)

1.32 hits per line