Version: Next

Higher Order Components

There are several cases where Struct components do not directly support a feature (ex. Suspense) or require a lot of boilerplate code to use the features (ex. Context).

In those cases, it is recommended to create function components that are higher-order components.

Higher Order Components Definition#

Higher Order Components are components that do not add any new HTML and only wrap some other components to provide extra functionality.

Example#

Hook into Context and pass it down to a struct component

use yew::prelude::*;

#[derive(Clone, Debug, PartialEq)]
struct Theme {
    foreground: String,
    background: String,
}

#[component]
pub fn App() -> Html {
    let ctx = use_state(|| Theme {
        foreground: "#000000".to_owned(),
        background: "#eeeeee".to_owned(),
    });

    html! {
        <ContextProvider<Theme> context={(*ctx).clone()}>
            <ThemedButtonHOC />
        </ContextProvider<Theme>>
    }
}

#[component]
pub fn ThemedButtonHOC() -> Html {
    let theme = use_context::<Theme>().expect("no ctx found");

    html! {<ThemedButtonStructComponent {theme} />}
}

#[derive(Properties, PartialEq)]
pub struct Props {
    pub theme: Theme,
}

struct ThemedButtonStructComponent;

impl Component for ThemedButtonStructComponent {
    type Message = ();
    type Properties = Props;

    fn create(_ctx: &Context<Self>) -> Self {
        Self
    }

    fn view(&self, ctx: &Context<Self>) -> Html {
        let theme = &ctx.props().theme;
        html! {
            <button style={format!(
                    "background: {}; color: {};",
                    theme.background,
                    theme.foreground
                )}
            >
                { "Click me!" }
            </button>
        }
    }
}

Edit this page