Rule clash between @typescript-eslint/init-declarations and no-undef-init

[xandris]

Given a stock config, local variables that may be undefined are impossible to lint:

// Variable 'x' should be initialized on declaration
// @typescript-eslint/init-declarations
let x: number | undefined

// It's not necessary to initialize 'x: number | undefined' to undefined
// no-undef-init
let x: number | undefined = undefined

The safer route is probably to turn off no-undef-init and allow superfluous initialization with undefined? At least in Typescript.

[mightyiam]

Sorry about this. And thank you for raising it. Will take a look. Perhaps this weekend.

[xandris]

I actually ended up turning off @typescript-eslint/init-declarations because for our codebase the problem it prevents is already caught by the Typescript compiler (TS2454 Variable is used before being assigned)

[mightyiam]

Thank you for the additional feedback, @xandris.

[mightyiam]

Analysis with @rostislav-simonik conclusion:
Both rules are desirable, except that typescript-eslint/typescript-eslint#9950.

@xandris would you concur?

We suggest waiting for upstream's response.

[xandris]

yes, i agree completely

[mightyiam]

typescript-eslint/typescript-eslint#9950 (comment)

@xandris say... how many of these do you have? Could they possibly be nicer as null instead?