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pastelInc/Validator.elm

Last active June 25, 2018 15:13
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I wanted to abstract Int and String and validate it by combining validation with function composition.
Raw
Validator.elm
module Validator
exposing
( ValidatableInput
, gte
, int
, lte
, mixAlpha
, mixLowercase
, mixNumeric
, mixSpecial
, mixUppercase
, required
, string
, validate
)
{-| This module can be combined some validations.
# Create
@docs ValidatableInput, int, string
# Use
@docs validate
# Common validations
@docs required, gte, lte, mixAlpha, mixNumeric, mixSpecial, mixUppercase, mixLowercase
-}
import Regex
{-| A validatable input
-}
type ValidatableInput
= ValidatableString Bool String
| ValidatableInt Bool Int
{-| Create a valid input from string
-}
string : String -> ValidatableInput
string input =
ValidatableString True input
{-| Create a valid input from integer
-}
int : Int -> ValidatableInput
int input =
ValidatableInt True input
isValid : ValidatableInput -> Bool
isValid input =
case input of
ValidatableString isValid _ ->
isValid
ValidatableInt isValid _ ->
isValid
{-| Validate the input.
input = string "Haruka"
validate required input == True
validate mixNumeric input == False
validate (required << mixNumeric) input == False
-}
validate : (ValidatableInput -> ValidatableInput) -> ValidatableInput -> Bool
validate operator =
isValid << operator
{-| Validate whether there is input.
name = string "Haruka"
age = int 17
empty = string ""
validate required name == True
validate required age == True
validate required empty == False
-}
required : ValidatableInput -> ValidatableInput
required input =
update requiredValidator input
requiredValidator : ValidatableInput -> Bool
requiredValidator input =
case input of
ValidatableString _ str ->
(not << String.isEmpty << String.trim) str
_ ->
True
update : (ValidatableInput -> Bool) -> ValidatableInput -> ValidatableInput
update op input =
case input of
ValidatableString isValid val ->
if isValid then
ValidatableString (op input) val
else
input
ValidatableInt isValid val ->
if isValid then
ValidatableInt (op input) val
else
input
{-| Validate if input is greater than or equal arbitrary value.
name = string "Haruka"
age = int 17
validate (gte "3") name == True
validate (gte "7") name == False
validate (gte "17") 17 == True
validate (gte "20") 17 == False
-}
gte : String -> ValidatableInput -> ValidatableInput
gte str input =
case String.toInt str of
Ok n ->
update (gteValidator n) input
Err _ ->
update (\_ -> False) input
gteValidator : Int -> ValidatableInput -> Bool
gteValidator x y =
case y of
ValidatableString _ strY ->
x <= String.length strY
ValidatableInt _ intY ->
x <= intY
{-| Validate if input is less than or equal arbitrary value.
name = string "Haruka"
age = int 17
validate (lte "3") name == True
validate (lte "-7") name == False
validate (lte "17") 17 == True
validate (lte "-20") 17 == False
-}
lte : String -> ValidatableInput -> ValidatableInput
lte str input =
case String.toInt str of
Ok n ->
update (lteValidator n) input
Err _ ->
update (\_ -> False) input
lteValidator : Int -> ValidatableInput -> Bool
lteValidator x y =
case y of
ValidatableString _ strY ->
x >= String.length strY
ValidatableInt _ intY ->
x >= intY
{-| Validate if input contains alphabets.
email = string "haruka17@example.com"
age = string "17"
validate mixAlpha email == True
validate mixAlpha age == False
-}
mixAlpha : ValidatableInput -> ValidatableInput
mixAlpha input =
mix (Regex.regex "[a-zA-Z]+") input
{-| Validate if input contains numbers.
validEmail = string "haruka17@example.com"
invalidEmail = string "haruka@exaple.com"
validate mixNumeric validEmail == True
validate mixNumeric invalidEmail == False
-}
mixNumeric : ValidatableInput -> ValidatableInput
mixNumeric input =
mix (Regex.regex "\\d+") input
{-| Validate if input contains special characters.
email = string "haruka17@example.com"
age = string "17"
validate mixSpecial email == True
validate mixSpecial age == False
-}
mixSpecial : ValidatableInput -> ValidatableInput
mixSpecial input =
mix (Regex.regex <| "[" ++ Regex.escape "!\"#$%&'()*+,-./\\:;?@[]^_`{|}~" ++ "]+") input
{-| Validate if input contains lowercase.
validEmail = string "haruka17@example.com"
invalidEmail = string "HARUKA17@EXAMPLE.COM"
validate mixLowercase validEmail == True
validate mixLowercase invalidEmail == False
-}
mixLowercase : ValidatableInput -> ValidatableInput
mixLowercase input =
mix (Regex.regex "[a-z]+") input
{-| Validate if input contains uppercase.
validEmail = string "HARUKA17@EXAMPLE.COM"
invalidEmail = string "haruka17@example.com"
validate mixUppercase validEmail == True
validate mixUppercase invalidEmail == False
-}
mixUppercase : ValidatableInput -> ValidatableInput
mixUppercase input =
mix (Regex.regex "[A-Z]+") input
mix : Regex.Regex -> ValidatableInput -> ValidatableInput
mix regex input =
update (mixValidator regex) input
mixValidator : Regex.Regex -> ValidatableInput -> Bool
mixValidator regex input =
case input of
ValidatableString _ str ->
Regex.contains regex str
_ ->
False
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