Form Validations in EmberJS

Question

I'm just wondering what the general pattern for validating forms in EmberJS? For my App.IndexView I have a form and when you click the submit button the target set to the view so I can do some validation. This works great up to the point where I need to do something with the fields that have errors. I would like to just add a class to the fields with errors but not really sure how to do it. Should the IndexView validate the form or should I create a view for each field that validates its self on blur? Below is what I have in my IndexView.

App.IndexView = Ember.View.extend


  create: (model) ->

    valid = @_validate model

    if valid is true
      @get('controller').send 'createUser'
    else
      # HANDLE THE FIELDS WITH ERRORS

  _validate: (model) ->

    invalid = []
    validations = {
      firstName: @_validateString model.get 'firstName'
      lastName: @_validateString model.get 'lastName'
      email: @_validateEmail model.get 'email'
      password: @_validatePassword model.get 'password'
      accountType: @_validateString model.get 'accountType'
    }

    # This will get all of the values then runs uniq to see if the
    # form is valid
    validForm = _.chain(validations).values().uniq().value()

    if validForm.length is 1 and validForm[0]
      true
    else
      # other wise build up an array of the fields with issues
      for field, val of validations
        if val is false
          invalid.push field

      invalid

  _validateString: (str) ->
    return false unless str
    if str isnt '' then true else false

  _validateEmail: (str) ->
    pattern = /^(([^<>()[\]\\.,;:\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,}))$/
    pattern.test str

  _validatePassword: (str) ->
    return false unless str
    if str.length >= 6 then true else false

and the template

<div class="row">
  <div class="span12">
    <div class="signup">
      <form class="form-horizontal offset3">
        <div class="control-group">
          <label class="control-label" for="first_name">First Name</label>
          <div class="controls">
            {{ view Ember.TextField placeholder="First Name" required="true" valueBinding='firstName' name='first_name' viewName='firstNameField'}}
          </div>
        </div>
        <div class="control-group">
          <label class="control-label" for="last_name">Last Name</label>
          <div class="controls">
            {{ view Ember.TextField placeholder="Last Name" required="true" valueBinding='lastName' name='last_name' viewName='lastNameField'}}
          </div>
        </div>
        <div class="control-group">
          <label class="control-label" for="email">Email</label>
          <div class="controls">
            {{ view Ember.TextField placeholder="Email" required="true" type="email" valueBinding='email' name='email' viewName='emailField'}}
          </div>
        </div>
        <div class="control-group">
          <label class="control-label" for="password">Password</label>
          <div class="controls">
            {{ view Ember.TextField placeholder="Password" required="true" type="password" valueBinding='password' name='password' viewName='passwordField'}}
          </div>
        </div>
        <div class="control-group">
          <label class="control-label" for="">Account Type</label>
          <div class="controls">
            {{#view Ember.RadioButtonGroup name="accountType" required="true" valueBinding="accountType"}}
              <label class="radio">
                {{view RadioButton checked='false' value="landlord"}}
                Landlord
              </label>
              <label class="radio">
                {{view RadioButton checked='false' required="true" value="tenant"}}
                Tenant
              </label>
            {{/view}}
          </div>

        </div>
        <div class="control-group">

          <div class="controls">
            <input class="btn btn-primary" {{action create model target='view' }} type="submit" value="Sign Up">
          </div>

        </div>
      </form>

    </div>

  </div>

</div>

Answer 1

I'm just wondering what the general pattern for validating forms in EmberJS?

There seem to be several patterns in use. It depends quite a bit on what is being validated, with the general strategy being to keep business logic far from the view layer as possible. Here are some links that may prove useful:

• validations-in-emberjs-application.html recommends performing validation at the controller level, with views are used to trigger validation when focus changes. This screencast demonstrates how this pattern can be used to validate a few simple form-fields.

• Asynchronous-Form-Field-Validation-With-Ember provides a few reusable components that can be used to perform simple validations at the view layer.

• ember-validations is a library that can be used to add active-record style validation capabilities to any ember-object

For my App.IndexView I have a form and when you click the submit button the target set to the view so I can do some validation. This works great up to the point where I need to do something with the fields that have errors. I would like to just add a class to the field of erro but not really sure how to do it.

since you're looking to validate a number of fields at once it might make more sense to move this validation logic into the controller. Either way, typically you would bind class attributes for a given field to a property as follows:

<div class="controls" {{bindAttr class=firstNameError:error:success}}>
  {{ view Ember.TextField placeholder="First Name" required="true" valueBinding='firstName' name='first_name' viewName='firstNameField'}}
</div>

So with this in place add a firstNameError property that returns true/false depending on results of your validation. Given your implementation it would probably make sense to set this property when _validate is run, but it could also be a computed property that performs validation in real-time.

Should the IndexView validate the form or should I create a view for each field that validates its self on blur?

That really depends on what you want the user experience to be like. FWIW my vote is to go with on-blur.