purescript-validation-experiment

What Is this

This repo is just a little test of the purescript-validation library, mainly for my own edification, but also hopefully to give an example of how both the Semigroup and Semiring versions of Data.Validation's V type can prove useful when validating input.

How Do I Use This?

First, ensure that you have node and npm installed.

Then, clone this repo...

git clone [email protected]:jkachmar/purescript-validation-experiment.git

...install the dependencies and build the project...

npm install  

...and run the example...

npm run validate

...which should print the following to the console:

Semigroup Validation:
(Invalid [(BadEmail [EmptyField,InvalidEmailAddress]),(BadPassword [EmptyField,NoSpecialCharacter,LessThanMinLength])])
(Invalid [(BadEmail [InvalidEmailAddress]),(BadPassword [NoSpecialCharacter])])
(Invalid [(BadPassword [NoSpecialCharacter])])
(Invalid [(BadPassword [LessThanMinLength])])
(Valid "{\"email\":\"[email protected]\",\"password\":\"abc123+-=\"}")


Semiring Validation:
Invalid ([(BadContact [EmptyField,InvalidEmailAddress,InvalidPhoneNumber]),(BadPassword [EmptyField,NoSpecialCharacter,LessThanMinLength])])
Invalid ([(BadContact [InvalidEmailAddress,InvalidPhoneNumber]),(BadPassword [NoSpecialCharacter])])
Invalid ([(BadPassword [NoSpecialCharacter])])
Invalid ([(BadPassword [LessThanMinLength])])
Invalid ([(BadContact [InvalidEmailAddress,InvalidPhoneNumber])])
Valid ("{\"contact\":{\"value0\":\"[email protected]\"},\"password\":\"abc123+-=\"}")
Valid ("{\"contact\":{\"value0\":\"+1 (555) 555-5555\"},\"password\":\"abc123+-=\"}")

Note that the Semiring validator has a record with a value0 key in its Valid results. This is due to the unsafe stringification of Contact, which is a sum type.

What's Going On Here?

To see a relatively straightforward validator whose Applicative instance uses Semigroup to accumulate errors, check out src/Semigroup.

To see a relatively straightforward validator that uses Semigroup to accumulate errors while performing validation with the Applicative instance, Semiring to accumulate errors while validation with the Alt instance, check out src/Semiring.