form-validator: A JavaScript repository from jgreene

A simple forms validation library meant to be used with browserify.

To install:

    npm install form-validator

To create a form (in coffee-script):

    validator = require 'formvalidator'

    check = validator.check

    FormValidator = validator.FormValidator

    registrationForm = new FormValidator()
    registrationForm.add 'email', (form) ->
        if form.email == ''
            'An email is required.'

    registrationForm.add 'email', (form) ->
        if form.email != '' and not check.isEmail form.email
            'Invalid email.'

    registrationForm.add 'password', (form) ->
        if form.password == ''
            'A password is required.'

    registrationForm.add 'confirmPassword', (form) ->
        if form.password != form.confirmPassword
            'Passwords must match.'

    exports.registrationForm = registrationForm


The key points from above are the instantiation of the FormValidator() type.  This type has 3 methods on it the first is the add method, this takes two arguments, the first is the name="" field of the input element you are validating.  This only tells the library which field you want your validation error associated with.  The second is a validation method, this method has a single argument that is the pre-parsed form (req.body); it also either returns a string (signifying an error) or nothing/null signifying no error.

Here is an example of checking a form server side:

    registrationForm = require('registrationForm').registrationForm

    app.post '/registration', (req, res) ->
        //errors is an array of { name: 'name', message: 'error message' }
        errors = registrationForm.validate req.body

        if errors.length > 0
            res.render 'registration', req.body
        else
            res.render 'success'

Here is an example of checking a form client side:
    
    <script type="text/javascript">
        var $ = require('jquery')
        var registrationForm = require('./registrationForm').registrationForm

        //attaches to the form by the form id
        $(document).ready(function() { registrationForm.clientSetup('registrationForm') })
    </script>

    <form id="registrationForm" action="/registration" method="post">
        
    </form>

Once your form is setup you can add error placeholders to it.  For field errors you can place an element with error="fieldName" on it to automatically display the error text when an error occurs. e.g.

    <span error="email"></span>

To display all errors you just need to add a <div class="formvalidation-errors"> container.  This will list all validation errors inside of it.

For some pre-made validators you can use:
    check = require('form-validator').check

This has a number of methods that will help make it easier to validate forms (contributions are appreciated).

That's it, if you have any questions please feel free to ask.
jgreene/form-validator
