Question about validation - Casting an input value to 'number'

I have an input that is supposed to contain a number. If I set the validation schema for this field to be yup.number().required(), when I go to edit the field it complains, likely since it is treating the input value as a string. I see from the yup docs that they have a cast method, but I’m not sure how to have formik attempt to cast values before/during validation.

Is there something I’m missing? Am I meant to manually specify this cast in mapValuesToPayload?

[agos]

input type number works, but is not available for select and, in general, for custom inputs

[johnrom]

I’d recommend doing something similar to @davidspiess above, except you can create a composable callback like this:

const stringToNumberConverter = stringValue => parseInt(stringValue, 10);
const parseAndHandleChange = (handleParse, handleChange) => event => {
    const value = handleParse(event.target.value);

    handleChange(event.target.name)(value);
}
const MyForm = () => {
    <Formik /* etc */>
        {(formikProps) => (
            <Field 
                name="myNumberField" 
                onChange={parseAndHandleChange(stringToNumberConverter, formikProps.handleChange)} 
            />
        )}
    </Formik>
}

FYI in v2 there are possible plans for an onParse-like API. Hopefully that will make things easier #1525