BB: Validation Plugin

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-alpha1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/handlebars.js/4.0.5/handlebars.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.3.3/backbone-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.validation/0.11.5/backbone-validation.js"></script>
<h1>Backbone Validation Ref</h1>

<script type="text/template" class="tmpl-person">
	<form action="" class="form-fields">
	
	<div>
		<label>Favorite Name:</label>
		<input type="text" class="js-input" name="favName" />
		<span class="feedback"></span>
		<ul class="error">This is a required field</ul>
	</div>
  
</form>
<br>
	<button class="btn  js-action--validate-favourite">Validate favourite name</button>
  
</script>

SCSS

@import url(http://fonts.googleapis.com/css?family=Roboto:300,400,500);

* {
  -webkit-font-smoothing: antialiased;
  box-sizing: border-box;
}

body {
    font-family: Roboto;
    padding: 16px;
    line-height: 1.5;
    font-weight: normal;
    color: #ccc;
    background: #292929;
    font-size: 18px;
}

h1, h2, h3 {
    font-weight: normal;
}

.pg-heading {
    margin-bottom: 0;
}

h1 {
	margin-bottom: 20px;
	font-size: 28px;
}

a {
    color: #95baf6;
    transition: opacity .3s;
}

a:hover {
    opacity: 0.75;
}

div {
	margin-bottom: 8px;
}

input,
button{
    border: none;
    height: 40px;
    outline: none;
    padding: 0 8px;
}

button {
	margin-right: 8px;
  margin-bottom: 8px;
	height: 50px;
}

input {
	width: 100%;
}

label {
	display: block;
}

button {
    padding: 0 16px;
    background: #2196F3;
    color: white;
    transition: background .3s;
		font-size: 18px;
		border-radius: 4px;
}

button:hover {
    background: #1E88E5;
}

button:active {
    background: #1976D2;
}

input[type=text] {
    transition: border-color .3s;
    border: 1px solid white;    
}

input ~ .error {
    color: red;
		display: none;
}

input.invalid ~ .error {
	display: block;
}

Babel + JSX

console.clear();

const Model = Backbone.Model.extend({

	validation: {
  	favName: [{
    	required: true,
			minLength: 3,
			msg: 'Name must be at least 3 characters long'
    }, {
			required: true,
			maxLength: 20,
			msg: 'Name can be no longer than 20 characters long'
		}, {
			required: true,
			msg: 'Name already exists',
			fn: 'checkForDuplicateName'
		}]
  },
	
  checkForDuplicateName(name) {
  	if (favsCollection.findWhere({
    	'favName': name
    })){
    	return 'error'
    }
	}
  
});

const Collection = Backbone.Collection.extend({
	initialize: function(models, options){
  	this.options = options;
  	this.listenTo(this, 'add', this.addToCollection, this);
  },
  
  addToCollection: function(model){
  	this.add(model);
  }
});

const View = Backbone.View.extend({
	template: Handlebars.compile( $('.tmpl-person').html() ),
	className: 'view',
	
  events: {
		'click .js-action--validate-favourite': 'actionValidate'
	},
	
	initialize() {
		Backbone.Validation.bind(this);
		
    this.fragment = document.createDocumentFragment();
    
		this.listenTo(this.model, {
			'validated': this.onModelValidated,
			'validated:valid': this.onModelValid,
			'validated:invalid': this.onModelInvalid,
			'invalid': this.onInvalid
		}); 
    
    var ua = window.navigator.userAgent;
    var msie = ua.indexOf('MSIE ');
    
    console.log('MSIE: ', msie);
    
	},
	
	render() {
		this.$el.html(this.template(this.model.toJSON()));
		return this;
	},
    
   /**
   * Save favourite clicked, set keys to 'favName' to match the input to validate
   * calls main validation function with keys and callback function
   * @param  {object} Click event from button
   */
  actionValidate(event){
  	event.preventDefault();
  	var keys = 'favName';
  	this.actionValidate(keys, this.saveFavourite.bind(this));  
  },
   
  /**
   * validate keys, get all inputs, create 'modelValues' obj, set model to this obj
   * sets 'isValid' top validate the keys
   * @param ...