Backbone forms validator

backbone-forms-validators.js

(function(){
    var validators = Backbone.Form.validators;

    //a validator verifying if an element is not in a given list
    validators.errMessages.notInList = 'Must not be in list {{list}}';
    validators.notInList = function(options) {
        if (!options.list) throw new Error('Missing required "list" options for "notInList" validator');

        options = _.extend({
          type:         'notInList',
          message:      this.errMessages.notInList
        }, options);
         
        return function notInList(value) {
            options.value = value;
          
            var err = {
                type: options.type,
                message: Form.helpers.createTemplate(options.message, options)
            };
          
            if (value === null || value === undefined || value === '') return;

            if(_.indexOf(options.list, value) != -1) return err;
        };
    };
})();