no-useless-undefined `: allow return undefined in promise.

[christopher-buss]

Description

In an async function, I want to be able to do return undefined at the end, to denote that I am intentionally not returning a value. Some ESLint Promise rules expect a return statement to silence specific warnings.

This could be added as an option, checkPromises.

For example, if I do:

const promise = somePromise.then(async () => {
	// some work
});
// `Each then() should return a value or throw - eslint-plugin-promise no-return`

To silence this warning, I would just do:

const promise = somePromise.then(async () => {
	// some work
	return undefined;
});
// `Do not use useless `undefined` - unicorn/no-useless-undefined`

Fail

"unicorn/no-useless-undefined": [ "error", { checkPromises: false }]

const promise = somePromise.then(async () => {
	// some work
	return undefined;
});
//

Pass

"unicorn/no-useless-undefined": [ "error", { checkPromises: true }]

const promise = somePromise.then(async () => {
	// some work
	return undefined;
});
//

Additional Info

No response

[fregante]

I don’t think it makes a difference whether the function is sync or async, it's unnecessary in both cases. If you disagree, you can disable the rule.

[christopher-buss]

It's necessary due to conflicts with other ESLint packages, and I don't want to disable the rule because I think it's useful. But I guess there will be no resolution here.