Example Folktale Composed Validations (needs work)

readme.md

This is an example of getting the same sort of validator definition that you have in angular (yeah who knew angular uses monads!!).

Needs a good bit more work.

• should automatically wrap the return value in Failure and Success.
• should not need to return an array. Should be an array by default.

demo.js

const {Success, Failure} = require( 'folktale/validation');
const R = require('ramda');

const isRequired = (form, field) => !!form[field].trim()
    ? Success([])
    : Failure(["This field is required"])

const isEmail = (form, field) => /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(form[field])
    ? Success([])
    : Failure([`${form[field]} doesn't seem to be an email`])

const isConfirmed = (fieldToConfirm, what) => (form, confirmField) => form[fieldToConfirm] === form[confirmField]
    ? Success([])
    : Failure([`${what} don't match`])

const mapEntries = require('folktale/core/object/map-entries')

const validate = (form, rules) => mapEntries(
    rules,
    ([field, fieldRules]) => {
    
        const possibleIssues = fieldRules.map(r => r(form, field))
                                         .reduce(R.concat, Success())
                                         .matchWith({
                                            Success: ({ value }) => value,
                                            Failure: ({ value }) => value
                                         })
        return [
            field,
            possibleIssues
        ]
    },
    (result, key, value) => R.assoc(key, value, result)
)

const form = {
    username: 'Jernej',
    email: 'jernej.sila@gmail',
    password: 'pass',
    password_confirmation: ''
}

const rules = {
    username:              [isRequired],
    email:                 [isRequired, isEmail],
    password:              [isRequired],
    password_confirmation: [isRequired, isConfirmed('password', 'Passwords')]
}

const errors = validate(form, rules)