Documentation

A function taking some value and returning a ValidatorResult

>>> Validator Text
Text -> ValidatorResult

>>> Validator Int
Int -> ValidatorResult

Validates a record field using a given validator function.

When the validation fails, the validation error is saved inside the meta :: MetaBag field of the record. You can retrieve a possible validation error using getValidationFailure.

Example: nonEmpty validation for a record

let project :: Project = newRecord
project
    |> validateField #name nonEmpty
    |> getValidationFailure #name -- Just "This field cannot be empty"


project
    |> set #name "Hello World"
    |> validateField #name nonEmpty
    |> getValidationFailure #name -- Nothing

Example: Using ifValid for branching

let project :: Project = newRecord

project
    |> validateField #name nonEmpty
    |> ifValid \case
        Left project -> do
            putStrLn "Invalid project. Please try again"
        Right project -> do
            putStrLn "Project is valid. Saving to database."
            createRecord project

A function taking some value and returning a 'IO ValidatorResult'

>>> ValidatorIO Text
Text -> IO ValidatorResult

>>> ValidatorIO Int
Int -> IO ValidatorResult

Validates a record field using a given validator function.

The same as validateField, but works with IO and can e.g. access the database.

When the validation fails, the validation error is saved inside the meta :: MetaBag field of the record. You can retrieve a possible validation error using getValidationFailure.

Overrides the error message of a given validator function.

>>> (nonEmpty |> withCustomErrorMessage "Custom error message") ""
Failure "Custom error message"

>>> (isEmail |> withCustomErrorMessage "We only accept valid email addresses") "not valid email"
Failure "We only accept valid email addresses"

Validates that value passes at least one of the given validators

>>> "ihp@example.com" |> validateAny([isEmptyValue, isEmail])
Success

>>> "" |> validateAny([isEmptyValue, isEmail])
Success

>>> "no spam plz" |> validateAny([empty, isEmail])
Failure "did not pass any validators"

Validates that value passes all of the given validators

In case of multiple failures, the first Failure is returned.

>>> 2016 |> validateAll([isGreaterThan(1900), isLessThan(2020)])
Success

>>> 1899 |> validateAll([isGreaterThan(1900), isLessThan(2020)])
Failure "has to be greater than 1900"

Validates that value is not empty

>>> nonEmpty "hello world"
Success

>>> nonEmpty ""
Failure "This field cannot be empty"

>>> nonEmpty (Just "hello")
Success

>>> nonEmpty Nothing
Failure "This field cannot be empty"

Validates that value is empty

>>> isEmptyValue "hello world"
Failure "This field must be empty"

>>> ieEmptyValue ""
Success

>>> isEmptyValue (Just "hello")
Failure "This field must be empty"

>>> isEmptyValue Nothing
Success

Validates that value looks like a phone number

Values needs to start with + and has to have atleast 5 characters

>>> isPhoneNumber "1337"
Failure ".."

>>> isPhoneNumber "+49123456789"
Success

Validates that value is an email address

The validation is not meant to be compliant with RFC 822. Its purpose is to reject obviously invalid values without false-negatives.

>>> isEmail "marc@digitallyinduced.com"
Success

>>> isEmail "marc@secret.digitallyinduced.com" -- subdomains are fine
Success

>>> isEmail "ॐ@मणिपद्मे.हूँ"
Success

>>> isEmail "marc@localhost" -- Although discouraged by ICANN, dotless TLDs are legal. See https://www.icann.org/news/announcement-2013-08-30-en
Success

>>> isEmail "loremipsum"
Failure "is not a valid email"

>>> isEmail "A@b@c@domain.com"
Failure "is not a valid email"

Validates that value is between min and max

>>> isInRange (0, 10) 5
Success

>>> isInRange (0, 10) 0
Success

>>> isInRange (0, 10) 1337
Failure "has to be between 0 and 10"

>>> let isHumanAge = isInRange (0, 100)
>>> isHumanAge 22
Success

Validates that value is less than a max value

>>> isLessThan 10 5
Success

>>> isLessThan 10 20
Failure "has to be less than 10"

Validates that value is greater than a min value

>>> isGreaterThan 10 20
Success

>>> isGreaterThan 10 5
Failure "has to be greater than 10"

Validates that value is equal to another value

>>> isEqual "foo" "foo"
Success

>>> isEqual "foo" "bar"
Failure "has to be equal to \"foo\""

Validates that value has a max length

>>> hasMaxLength 10 "IHP"
Success

>>> hasMaxLength 2 "IHP"
Failure "is longer than 2 characters"

Validates that value has a min length

>>> hasMinLength 2 "IHP"
Success

>>> hasMinLength 10 "IHP"
Failure "is shorter than 10 characters"

Validates that value is a hex-based rgb color string

>>> isRgbHexColor "#ffffff"
Success

>>> isRgbHexColor "#fff"
Success

>>> isRgbHexColor "rgb(0, 0, 0)"
Failure "is not a valid rgb hex color"

Validates that value is a hex-based rgb color string

>>> isRgbaHexColor "#ffffffff"
Success

>>> isRgbaHexColor "#ffff"
Success

>>> isRgbaHexColor "rgb(0, 0, 0, 1)"
Failure "is not a valid rgba hex color"

Validates that value is a hex-based rgb(a) color string

>>> isHexColor "#ffffff"
Success

>>> isHexColor "#ffffffff"
Success

>>> isHexColor "rgb(0, 0, 0)"
Failure "is not a valid hex color"

Validates that value is a rgb() color string

>>> isRgbColor "rgb(255, 0, 0)"
Success

>>> isRgbColor "#f00"
Failure "is not a valid rgb() color"

Validates that value is a rgba() color string

>>> isRgbaColor "rgb(255, 0, 0, 1.0)"
Success

>>> isRgbaColor "#f00f"
Failure "is not a valid rgba() color"

Validates that value is a hex-based or rgb(a) color string

>>> isColor "#ffffff"
Success

>>> isColor "rgba(255, 0, 0, 0.5)"
Success

>>> isColor "rgb(0, 0, 0)"
Failure "is not a valid color"

Validates string starts with http:// or https://

>>> isUrl "https://digitallyinduced.com"
Success

>>> isUrl "digitallyinduced.com"
Failure "is not a valid url. It needs to start with http:// or https://"

Validates that value is True

>>> isTrue True
Success

>>> isTrue False
Failure "This field cannot be false"

Validates that value is False

>>> isFalse False
Success

>>> isFalse True
Failure "This field cannot be true"

Validates that value is matched by the regular expression

>>> matchesRegex "^[0-9]{4}$" "2016"
Success

>>> matchesRegex "^[0-9]{4}$" "16"
Failure "This field does not match the regular expression \"^[0-9]{4}$\""

>>> matchesRegex "[0-9]{4}" "xx2016xx"
Success -- regex is missing ^ and $

Validates that value is a valid slug

>>> isSlug "i-am-a-slug"
Success

>>> isSlug "I-AM-A-Slug (Copy)"
Failure "is not a valid slug (consisting of only letters, numbers, underscores or hyphens)"