Our JavaScript at this point is basically an add only nightmare I have no idea how to dig ourselves out of.

It is a bigger problem than I know how to fix. We even have a similar static analysis tool on our code, but when there are thousands and thousands of existing issues pointed out by it no one really cares about adding a few more to the pile.

I tried to promote typescript and rewriting over time. I can’t seem to get our front end developers to understand the value, or care. It’s totally my failure; it hurts my soul.

It’s honest to god something of an existential crisis for me.

I hunkered down in primarily backend over the nightmare that is our JS, whereas I spent nearly ten years full stack. Sigh.

Here is the method I used in a similar situation. Start from an extremely loyal linter config where you get 0 errors and 0 warnings with your existing code (that might mean an empty config, but that's OK). Then add rules one by one, fixing the codebase completely for each rule that you add, so that you always have 0 warnings and 0 errors with each commit. Yes, this is significant amount of work, but at least the work is broken down into chunks, and each chunk has a clear definition of done (can go straight into an agile backlog, etc). By the time you have a sensible linter config, you have a much better codebase as well.

Ditto, this is the same thing I did for a 16,000+ line app.

I used eslint ( https://eslint.org ) and prettier ( https://prettier.io ), and using airbnb's JavaScript Style Guide as a reference point ( https://github.com/airbnb/javascript ), I would enable rules one by one. Then slowly rule by rule (commit by commit) I would clean up the code base.