Function yew::functional::use_effect_with_deps

pub fn use_effect_with_deps<'hook, T, F, D>(
    f: F,
    deps: T
) -> impl 'hook + Hook<Output = ()>where
    T: PartialEq + 'static,
    F: FnOnce(&T) -> D + 'static,
    D: TearDown,
    T: 'hook,
    F: 'hook,
    D: 'hook,

This hook is similar to use_effect but it accepts dependencies.

Whenever the dependencies are changed, the effect callback is called again. To detect changes, dependencies must implement PartialEq.

Note

The destructor also runs when dependencies change.

Example

use yew::{function_component, html, use_effect_with_deps, Html, Properties};

#[derive(Properties, PartialEq)]
pub struct Props {
    pub is_loading: bool,
}

#[function_component]
fn HelloWorld(props: &Props) -> Html {
    let is_loading = props.is_loading.clone();

    use_effect_with_deps(
        move |_| {
            log!(" Is loading prop changed!");
        },
        is_loading,
    );

    html! { <>{"Am I loading? - "}{is_loading}</> }
}

Tips

Only on first render

Provide a empty tuple () as dependencies when you need to do something only on the first render of a component.

use yew::{function_component, html, use_effect_with_deps, Html};

#[function_component]
fn HelloWorld() -> Html {
    use_effect_with_deps(
        move |_| {
            log!("I got rendered, yay!");
        },
        (),
    );

    html! { "Hello" }
}

On destructing or last render

Use Only on first render but put the code in the cleanup function. It will only get called when the component is removed from view / gets destroyed.

use yew::{function_component, html, use_effect_with_deps, Html};

#[function_component]
fn HelloWorld() -> Html {
    use_effect_with_deps(
        move |_| {
            || {
                log!("Noo dont kill me, ahhh!");
            }
        },
        (),
    );
    html! { "Hello" }
}

Any type implementing TearDown can be used as destructor

Tip

The callback can return [()] if there is no destructor to run.

Note

When used in function components and hooks, this hook is equivalent to:

pub fn use_effect_with_deps<T, F, D>(f: F, deps: T)
where
    T: PartialEq + 'static,
    F: FnOnce(&T) -> D + 'static,
    D: TearDown,
{
    /* implementation omitted */
}