Add ability to pass context for validation

[KhodeN]

🚀 Feature request

Current Behavior

I can use only pure validation schemas (for validationSchema prop).

Desired Behavior

Ability to pass context argument for validateAt function inside Formik.

https://github.com/jquense/yup#mixedvalidatevalue-any-options-object-promiseany-validationerror

Suggested Solution

Add validationContext optional prop for and pass it as schema.validateAt(field, values, {context})

Or, more customizable, add validationOptions and pass it as schema.validateAt(field, values, options)

Who does this impact? Who is this for?

It may be useful for checking the entry in the list of values ​​loaded later (e.g., constants or dictionaries). In custom function in when, for example.

Or for tuning validation, see https://github.com/jquense/yup#mixedwhenkeys-string--arraystring-builder-object--value-schema-schema-schema example

Describe alternatives you've considered

custom function for validate prop, but this solution is ugly

[kaldebert]

👍 This is a must-have feature ! Can't wait to have this.

[codecadwallader]

custom function for validate prop, but this solution is ugly

@KhodeN Looks like this is still an open issue.. do you recall at all what happened when trying to customize the validate prop that made it ugly? I'm probably going to head in this direction..

[codecadwallader]

Recommend looking at work-around in #506 for anyone else coming to this issue (i.e. define validate function to mimic the validationSchema behavior).

[egemon]

+1 to feature