Catch unexpected chars at build time

[archmoj]

Guard against issue #5382.

@plotly/plotly_js

[archmoj]

Also noticed in #5416 (comment).

[alexcjohnson]

I'm not quite sure I understand this rule, it looks like it only applies to regular expressions in the code. Can you verify that this command fails prior to the fix in #5382?

[archmoj]

I'm not quite sure I understand this rule, it looks like it only applies to regular expressions in the code. Can you verify that this command fails prior to the fix in #5382?

Yes I did verify that. Eslint catched the problem. But I am not 100% sure about that rule. Maybe we could just run eslint with an empty rule?

[alexcjohnson]

Maybe we could just run eslint with an empty rule?

Haha interesting concept - yes, I suppose if eslint is simply unable to parse the file it would fail even without a rule. Anyway since you've shown this is a valuable check, let's go with it as is. 💃