Description
Repro
Given the following config, it seems that there is an unresolvable conflict:
{
"rules": {
"require-await": "error",
"no-return-await": "error",
"@typescript-eslint/promise-function-async": "error"
}
}A function that returns a promise, such as:
function numberOne(): Promise<number> {
return Promise.resolve(1);
}..triggers @typescript-eslint/promise-function-async with the warning:
Functions that return promises must be async
Adding the async keyword:
async function numberOne(): Promise<number> {
return Promise.resolve(1);
}..then triggers require-await with the warning:
async function ’numberOne’ has no ‘await’ expression
Finally, adding the await keyword:
async function numberOne(): Promise<number> {
return await Promise.resolve(1);
}..then triggers no-return-await with the warning:
Redundant use of ‘await’ on a return value
Expected Result
No errors
Actual Result
(see repro above)
Additional Info
Individually, each of the configured rules address a legitimate problem. But together they appear to be mutually exclusive.
Over in ESlint core, there was a discussion on whether an async function that returns the result of another async function should be allowed to omit the await keyword without triggering require-await.
As @kaicataldo points out though, it isn’t really possible because ESLint is constrained by the limits of static analysis, and suggests that the help of a typing system (e.g Typescript) would be needed to implement this exception.
Hence I’m raising the issue here, to gather feedback on whether this implies the need for a @typescript-eslint/require-await version of the base rule.
Versions
| package | version |
|---|---|
@typescript-eslint/eslint-plugin |
1.10.2 |
@typescript-eslint/parser |
1.10.2 |
TypeScript |
3.5.1 |
ESLint |
5.16.0 |
node |
12.1.0 |
npm |
6.9.0 |