TypeScript doesn't use the name of the type while inferring return type

[jbhoot]

For a function

const toFirstName = (input: string) => R.fromPredicate(input, S.isNotEmpty, 'Enter your first name');

the return type is inferred as

which is technically true, but I would have preferred the inferred type to be the same as that of R.fromPredicate()

Right now, I need to specify the return type explicitly as

const toFirstName = (input: string): Result<string, string> => R.fromPredicate(input, S.isNotEmpty, 'Enter your first name');

[mobily]

@jayesh-bhoot I assume that something is wrong on your side, on my end the type is inferred and narrowed correctly:

it works fine with flow as well:

[jbhoot]

You are right. This problem shows up on IntelliJ WebStorm, but not on Visual Studio Code.

[jbhoot]

Tracking the issue at https://youtrack.jetbrains.com/issue/WEB-57226/Type-sometimes-isnt-inferred-correctly-The-type-hint-shows-the-structure-of-the-type-instead-of-its-name