Package validator implements structure and field validation, including cross fields, cross structures, maps, slices and arrays.

• Customizable i18n aware error messages.
• Handles custom field types such as sql driver Valuer.
• Ability to dive into both map keys and values for validation.
• Handles type interface by determining it's underlying type prior to validation.
• Cross Field and Cross Struct validations by using validation tags or custom validators.
• Slice, Array and Map diving, which allows any or all levels of a multidimensional field to be validated.
• Alias validation tags, which allows for mapping of several validations to a single tag for easier defining of validations on structs.
• Extraction of custom defined Field Name e.g. can specify to extract the JSON name while validating and have it available in the resulting FieldError.

	go get github.com/pchchv/validator

And

	import "github.com/pchchv/validator"

• If new to using validator it is highly recommended to initialize it using the WithRequiredStructEnabled option which is opt-in to new behaviour that will become the default behaviour in v11+. See documentation for more details.

validate := validator.New(validator.WithRequiredStructEnabled())

Validator only returns InvalidValidationError for bad input validation, nil or ValidationErrors as a type error. So all to do is to check if the returned error is nil, and if not, check if the error is InvalidValidationError (if necessary, most of the time it is not), cast it to the ValidationErrors type as shown below:

err := validate.Struct(mystruct)
validationErrors := err.(validator.ValidationErrors)

• Simple
• Struct Level
• Custom Field Types
• Gin upgrade and/or override validator