* Improve ESLint setup
- Uses `eslint:recommended` + a handful more rules.
- Uses .eslintignore so that editors can understand which files to lint.
- Uses .eslintrc<strong>.js</strong> so more editors get syntax highlighting.
* Fix ESLint errors
About half of them were fixed by `eslint . --fix`.
This commit updates `npm run format:all` to not only format .js files in
src/ and bin/, but also tests_config/ and scripts/, as well as all
jsfmt.spec.js files.
It also includes the result of running `npm run format:all`, except
changes to src/ and bin/.
* Extract custom tests from tests/flow/
Approach:
1. Remove all .js files in tests/flow except .snap.js files.
2. Copy over all .js files from tests/ in the flow repo.
3. Go through the diff looking for deletions.
- It was easy to see which deletions were due to changes in the tests
due to updates in the flow repo.
- For the rest of the deletions, I used `git blame` to verify that
they had been added by us since the flow tests were copied over.
This makes tests/flow/ simply a copy of the tests from the flow repo,
making it easier to sync with the upstream flow tests in the future.
* Add a script for syncing the flow tests
* Sync the flow tests