export default { plainObject : function ( obj ) : boolean { return typeof obj == "object" && ! ( obj instanceof Array ) && obj instanceof Object ; } , aFunction : function ( obj ) : boolean { return typeof obj == "function" ; } , string : function ( obj ) : boolean { return typeof obj == "string" ; } , array : function ( obj ) : boolean { return obj instanceof Array ; } , number : function ( obj ) : boolean { return typeof obj == "number" && ! isNaN ( obj ) ; } } ;