Add no-floating-promises @typescript-eslint rule

[lksnmnn]

What do you want and why?

Adding the above mentioned rule, would catch floating promises and thus helps devs like me to not forget to await my promises.

Discussion:

The ESLint rule require-await does something similar but cannot gather insights about functions imported from other files and thus flags false positives like:

const foo = async () => {
    return bar()
}

Possible implementation(s)

"@typescript-eslint/eslint-plugin": 
"@typescript-eslint/parser": 

Additional context

Add any other context or screenshots about the feature request here.

[flybayer]

Probably it's good to add that one, but to prevent issues where you forget to await a promise, we actually need @typescript-eslint/no-floating-promises which requires using typescript as a parser.

We are currently using that in the blitz monorepo like so: https://github.com/blitz-js/blitz/blob/canary/.eslintrc.js#L55-L66

Probably it's a good idea to add to our blitz eslint config for users. It will add two new dependencies,

"@typescript-eslint/eslint-plugin": 
"@typescript-eslint/parser": 

[Roesh]

I think this definitely should be set to warn

[lksnmnn]

I've now looked into this and maybe I should rewrite this issue to reflect that we need to add the no-floating-promises rule rather than require-await. Because with the latter rule, this gets flagged:

const foo = async () => {
    return bar()
}

and changing this to return await bar() is discouraged my the no-return-await rule, since it adds a small perfomance hit.

[flybayer]

@lksnmnn sounds good to me to update the issue

[lksnmnn]

Updated the issue to reflect our discussion.

[flybayer]

For whoever wants to work on this, our eslint config is here: https://github.com/blitz-js/blitz/tree/canary/packages/eslint-config You'll need to add the correct dependencies to that package as well as the config file.

[satya-nutella]

@flybayer Number 5? Can I hop on this one?

[flybayer]

@meehawk sorry for the delay, of course! Btw, you don't have to wait for confirmation if it's labeled status/ready-to-work-on