DefinitelyTyped VS typescript-eslint

Yes, that's correct... compose() pipes a bunch of passed functions from right to left. Here's the actual type definition if you want to see: https://github.com/googol/DefinitelyTyped/blob/6836f798cb186...

But even at its simplest variant, with just one or two functions passed, what the V0 or T1 do is pretty confusing. I thiiiiiiiiink it's trying to ensure the return type of one function is correctly passed as the input type of the subsequent function, and so on and so forth, but I don't really know.

Also, I should note that I'm using an older version of that lib. The latest version has cleaner typings... still difficult, but at least formatted better: https://github.com/DefinitelyTyped/DefinitelyTyped/blob/mast...

Typescript-eslint can assist in this task. This tool helps identify all instances of unsafe any usage. Specifically, all usages of JSON.parse can be found and it can be ensured that the received data's format is checked. More about getting rid of the any type in a codebase can be read in the article Making TypeScript Truly "Strongly Typed".

> Only lint files that have changed? How hard that is?

Quite hard, especially since type-aware rules from e.g. https://typescript-eslint.io/ mean that changing the type of a variable in file A can break your code in file B, even if file B hasn't changed.

The article only touches this: when converting to TypeScript, `any` is useful, but in the end you don't want this type in your codebase - so don't forget to use typescript-eslint [0] and turn on those no-unsafe-* rules which guard against `any` leaking into your code.

[0] https://github.com/typescript-eslint/typescript-eslint

By convention, React components should be named in PascalCase. @typescript-eslint has the config we need, and though we can't specifically target React components, we can target variables (and set some other conventions while we're at it):