Sets default error messages for a given validator across all structs ex: errMap := map[string]{ "required": "This is field is required", "email": "This must be na email", }.

Registers a struct instance{} with a map of errors so that the Validator maps errors to a given validator t is an instance of the struct that is going to be validated fieldErrMap key follows the pattern: fieldErrMap := map[string]string{ "FirstName.validator": "First Name is Required", "_default.required": "Field is Required", "_default": "This field is required", }.