* Lint arrow-body-style
* Lint prefer-object-spread
Object spread is faster _and_ more readable.
This also fixes a few unnecessary object clones.
* Enable no-parameter-properties
This isn't currently used, but this makes clear that it shouldn't be.
* Refactor more Promises to async/await
* Remove unnecessary code from getDataMoveHTML etc
* Lint prefer-string-starts-ends-with
* Stop using no-undef
According to the typescript-eslint FAQ, this is redundant with
TypeScript, and they're not wrong. This will save us from needing to
specify globals in two different places which will be nice.
Previously, ending a read stream was `stream.push(null)`, and ending a
write stream was `stream.end()`. This was often confusing, and so now,
these are consistently `stream.pushEnd()` and `stream.writeEnd()`.
This refactor already found a bug in which `stream.end()` was used
where `stream.push(null)` should have been.
Also in this refactor: By default, `pushError` ends the stream. You can
pass `true` as the second parameter if the error is recoverable (the
stream shouldn't end).
