[−][src]Trait yew::html::Component
Components are the basic building blocks of the UI in a Yew app. Each Component chooses how to display itself using received props and self-managed state. Components can be dynamic and interactive by declaring messages that are triggered and handled asynchronously. This async update mechanism is inspired by Elm and the actor model used in the Actix framework.
Associated Types
type Message: 'static
Messages are used to make Components dynamic and interactive. Simple
Component's can declare their Message type to be ()
. Complex Component's
commonly use an enum to declare multiple Message types.
type Properties: Properties
Properties are the inputs to a Component and should not mutated within a Component. They are passed to a Component using a JSX-style syntax.
html! { <Model prop="value" /> }
Required methods
fn create(props: Self::Properties, link: ComponentLink<Self>) -> Self
Components are created with their properties as well as a ComponentLink
which
can be used to send messages and create callbacks for triggering updates.
fn update(&mut self, msg: Self::Message) -> ShouldRender
Components handle messages in their update
method and commonly use this method
to update their state and (optionally) re-render themselves.
fn change(&mut self, _props: Self::Properties) -> ShouldRender
When the parent of a Component is re-rendered, it will either be re-created or
receive new properties in the change
lifecycle method. Component's can choose
to re-render if the new properties are different than the previously
received properties. Most Component's will use props with a PartialEq
impl and will be implemented like this:
fn change(&mut self, props: Self::Properties) -> ShouldRender { if self.props != props { self.props = props; true } else { false } }
Components which don't have properties should always return false.
fn view(&self) -> Html
Components define their visual layout using a JSX-style syntax through the use of the
html!
procedural macro. The full guide to using the macro can be found in Yew's
documentation.
Provided methods
fn rendered(&mut self, _first_render: bool)
The rendered
method is called after each time a Component is rendered but
before the browser updates the page.
Examples
fn rendered(&mut self, first_render: bool) { if first_render { self.setup_element(); // Similar to 'mounted' in other frameworks } }
fn destroy(&mut self)
The destroy
method is called right before a Component is unmounted.