Some addition validators for Backbone.Form

Backbone.Form.Validators.js

(function (Form) {
    Form.validators.errMessages = {
        youtube: 'Enter link from YouTube',
        positive_int: 'Enter positive integer'
    };
    
    Form.validators.youtube = function(options) {
        options = _.extend({
          type: 'youtube',
          message: this.errMessages.youtube,
          regexp: /^(http|https):\/\/(www\.youtube\.com|youtu.be)\/[a-zA-Z0-9\?&\/=\-]+$/gmi
        }, options);
        
        return Form.validators.regexp(options);
    };
    
    Form.validators.positive_int = function(options) {
        options = _.extend({
          type: 'positive_int',
          message: this.errMessages.positive_int
        }, options);
         
        return function positive_int(value) {
          options.value = value;
          
          var err = {
            type: options.type,
            message: options.message
          };
          
          if (value === null || value === undefined || value === false || value === '' || value <= 0) return err;
        };
    };
}(Backbone.Form));