code: function Customisable() {
  		this.custom = {};
  
  		this.extend = function (custom) {
  			return _extend(this.custom, custom);
  		};
  
  		this.reset = function () {
  			this.custom = {};
  		};
  
  		this.remove = function (fields) {
  			if (!_typeIs.array(fields)) {
  				fields = [fields];
  			}
  			fields.forEach(function (field) {
  				delete this.custom[field];
  			}, this);
  		};
  	}
docs: Customisable class (Base class) ------------------------------------------- Use with operation "new" to extend Validation and Sanitization themselves, not their prototype. In other words, constructor shall be call to extend those functions, instead of being in their constructor, like this: _extend(Validation, new Customisable);