This simply upgrades eslint but also activates some rules for implicit rules we've had before but never explicitly stated, and inconsistencies that are easily sorted out by an eslint plugin.
Set of changes
The nullish coalescing, nullish coalescing assignment, and optional chaining operators are now restricted
This was implicit before, however, as this is untranspiled (as per our rule of not using transpiled syntax), this is not in our browser support and must be avoided (outside of tests)
Sequence expressions are now restricted
We only used a sequence expression once and that was an accidental usage. Outside of for-statements we never use them and they should just be disabled for the codebase, since the minifier does a better job at automatically using them as needed
Multiple declarators in a variable declarations are now restricted
We're very consistent about having one variable declarator per declaration, so this should be enforced
We now activate a rule to make type imports consistent and to avoid side-effect imports where it's unnecessary
Prettier has been upgraded, which adds a bunch of changes
Summary
This simply upgrades eslint but also activates some rules for implicit rules we've had before but never explicitly stated, and inconsistencies that are easily sorted out by an eslint plugin.
Set of changes
typeimports consistent and to avoid side-effect imports where it's unnecessary