Formik: Validation behavior inconsistent

[michelalbers]

Current Behavior

If the validate property is an async function it expects the errors to be thrown instead of returned. See source file Formik.tsx: https://github.com/jaredpalmer/formik/blob/0df51c2cdda3d01c65fabdbc8f3b6f443a7b0f2e/src/Formik.tsx#L215-L233

Synchronous validation functions need to return the error object instead. IMHO this is inconsistent and should be either throw or return for both cases.

Steps to Reproduce

Write a simple validation function and make it async. Errors will magically disappear until you throw them instead of returning.

Will not validate

<Formik
   validate={() => ({ fooField: 'Foo is required!' })}
>
  {/* MyForm */}
</Formik>

Will validate

<Formik
   validate={async () => ({ fooField: 'Foo is required!' })}
>
  {/* MyForm */}
</Formik>

Expected behavior

Errors should either be returned or thrown in both cases.

Suggested solution(s)

I'll open a PR where its returned in both cases if everyone agrees on my opinion. But let's discuss it.

Additional Info

The documentation describes this behavior - so probably not an issue for new devs. Still - what do you guys & girls think?

[michelalbers]

@jaredpalmer any thoughts or should I just close this?

[prichodko]

I agree, it seems to me that it isn't very intuitive to throw in async validate rather then simply return them like in regular validate.

[michelalbers]

PR is open. I guess this could be something for the next major release since it is a breaking change.

[soundyogi]

+1

[NeoLegends]

I just ran into this and spent half an hour wondering why validation wasn't working as soon as I made it asynchronous. Would be great to land this soon!

[jannikbuschke]

Im also running into problems with this design. Its difficult to differentiate between real unexpected runtime errors and expected validation errors.

[jaredpalmer]

this will fixed in v2