# Bio: list of the supported modifiers The modifiers are attributes starting with a `@` and are followed by the modified attribute. This will allow the user to organize his data knowing the effect of each of these modifiers. ## 0.0.0.2021 ### 6.1

Private modifiers
> - `@private`: default modification of an attribute. > - `@resolver` (readonly): in Async Components, Bio needs to know which method is used to render the component. Using this modifier will save the attribute as the resolver > - `@neutral`: if the user wants the attribute not to be reactive > - `@void` (readonly): saves readonly methods. > - `@mutable` (readonly): the attribute will act as a getter and will update automatically, when a dependency is changed. > - `@store`: the `@store` modifier will pick the attribute from the imported Store Component. > - `@emit` (readonly, node): the attribute will be used as an emitter to the parent/child component.
Public modifiers
> - `@public`: this modification allows parent component and the component, to change the attribute. it acts like a property > - `@in`: this modification allows only the parent component to change the attribute. > - `@required`: this modification allows only the parent component to change the attribute, this set the attribute as required, so the attribute can't be undefined.
Configuration modifiers
> - `@url`: url parameter value injected to the attribute. > - `@config`: the `@config` modifier can only be assigned to the root of the application. the attribute adds its value to the application configuration > - `@env`: get the variable of environment

### 6.2 > syntax: `AttributeModifier[[AttributeType][ Attribute|AttributeBoolean AttributeValue` ```ts export component ] users @void sayHello={() => console.log(`Hello ${this.name}`)}> ... ``` ### 6.3 > all attributes are private by default, if no value is provided they are set to true.