One entry of a batch validation: the value, the validator to run on it, and how to name it.
The value to check.
Validator applied to value; must return the { valid, error } shape.
value
{ valid, error }
Optional
Options forwarded to validator.
validator
Human-readable name used to prefix this entry's message in the aggregate result.
One entry of a batch validation: the value, the validator to run on it, and how to name it.