Fix all eslint errors and warnings

[terror]

We're currently breaking every eslint rule in existence, it would be nice to fix that up and get eslint running in CI.

n.b. eslint --fix can do some of the work.

[boxizen]

It would be better to add project checking and formatting before submission in the project, otherwise some irregular codes will inevitably be added later.

[terror]

It would be better to add project checking and formatting before submission in the project, otherwise some irregular codes will inevitably be added later.

Yep that's the goal! As a prerequisite we need to fix the current state of the code base before we add a check in CI.

[truell20]

Thanks for the prs here!