How to validate name of a function?

[itsramiel]

Hi, I would like to make sure that a variable is a function but also check that the name of the function is of a specific value.

How can I do that?

One solution I guess is to pipe function with custom and check in custom, but the issue is the value passed to custom is of typeunknown and not function like this:

v.pipe(
    v.function()
    v.custom(fn => ...)
)

Or

v.custom(
    (value) => typeof value === 'function' && value.name === 'name'
  )

but I was wondering if there is a better way?
Perhaps function could accept a name?

[fabian-hiller]

You should use check instead of custom. Try it out in our playground.

import * as v from 'valibot';

const Schema = v.pipe(
  v.function(),
  v.check(
    (func) => func.name === 'foo',
    (issue) => `The name is "${issue.input.name}" instead of "foo"`,
  ),
);

[fabian-hiller]

custom is a schema, while check is a validation action. Schemas always expect unknown input. You may want to take a look at our mental model: https://valibot.dev/guides/mental-model/

[itsramiel]

Alright, thank you 🙏