Function leptos_reactive::create_isomorphic_effect

pub fn create_isomorphic_effect<T>(
    cx: Scope,
    f: impl Fn(Option<T>) -> T + 'static
)where
    T: 'static,

Creates an effect; unlike effects created by create_effect, isomorphic effects will run on the server as well as the client.

let (a, set_a) = create_signal(cx, 0);
let (b, set_b) = create_signal(cx, 0);

// ✅ use effects to interact between reactive state and the outside world
create_isomorphic_effect(cx, move |_| {
  // immediately prints "Value: 0" and subscribes to `a`
  log::debug!("Value: {}", a());
});

set_a(1);
// ✅ because it's subscribed to `a`, the effect reruns and prints "Value: 1"

// ❌ don't use effects to synchronize state within the reactive system
create_isomorphic_effect(cx, move |_| {
  // this technically works but can cause unnecessary re-renders
  // and easily lead to problems like infinite loops
  set_b(a() + 1);
});