The type of the key of the input record.
OptionalarrayHow to resolve any arrays provided in the data (can either stringify them or add them multiple times).
OptionalnullableOptionalnullHow to resolve null data (May either stringify to 'null', resolve to an empty string, or omit entirely).
OptionalundefinedHow to resolve undefined data (May either stringify to 'undefined', resolve to an empty string, or omit entirely).
Options for resolving form data when it may be undefined or null, but not both.