Struct Observer 

pub struct Observer { /* private fields */ }

Runs a closure while recording which reactive values it reads, and calls on_invalidate (once per run) when any of them changes.

Implementations

impl Observer

pub fn new(on_invalidate: impl Fn() + 'static) -> Self

Creates a dirty observer that calls on_invalidate when a tracked dependency changes.

use std::cell::Cell;
use std::rc::Rc;
use ravenrs_reactive::{Observer, State};

let name = State::new("Ada".to_string());
let hits = Rc::new(Cell::new(0));
let h = hits.clone();
let observer = Observer::new(move || h.set(h.get() + 1));
observer.track(|| name.get());
name.set("Grace".to_string());
assert_eq!(hits.get(), 1);
assert!(observer.is_dirty());

pub fn track<R>(&self, f: impl FnOnce() -> R) -> R

Runs f, replacing the previous dependency set with what f reads.

pub fn untracked<R>(f: impl FnOnce() -> R) -> R

Runs f without recording dependencies for any observer.

pub fn is_dirty(&self) -> bool

True until the first track and after any dependency changed.

pub fn invalidate(&self)

Marks the observer dirty and fires its callback, as if a dependency changed.

Trait Implementations

impl Debug for Observer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.