Struct silkenweb_reactive::signal::ReadSignal
source · pub struct ReadSignal<T>(_);
Expand description
Receive changes from a signal.
Changes will stop being received when this is destroyed:
let x = Signal::new(1);
let seen_by_y = Rc::new(Cell::new(0));
let y = x.read().map({
clone!(seen_by_y);
move|&x| seen_by_y.set(x)
});
assert_eq!(seen_by_y.get(), 1);
x.write().set(2);
assert_eq!(seen_by_y.get(), 2);
mem::drop(y);
// We won't see this update
x.write().set(3);
assert_eq!(seen_by_y.get(), 2);
Implementations§
source§impl<T: 'static> ReadSignal<T>
impl<T: 'static> ReadSignal<T>
sourcepub fn only_changes(&self) -> ReadSignal<T>where
T: Clone + Eq,
pub fn only_changes(&self) -> ReadSignal<T>where
T: Clone + Eq,
Only propagate actual changes to the signal value.
let all_updates_count = Rc::new(Cell::new(0));
let only_changes_count = Rc::new(Cell::new(0));
let x = Signal::new(0);
let all_updates = x.read().map({
clone!(all_updates_count);
move |_| all_updates_count.set(all_updates_count.get() + 1)
});
let only_changes = x.read().only_changes().map({
clone!(only_changes_count);
move |_| only_changes_count.set(only_changes_count.get() + 1)
});
x.write().set(1);
x.write().set(1);
assert_eq!(all_updates_count.get(), 3, "One for init + 2 updates");
assert_eq!(only_changes_count.get(), 2, "One for init + 1 actual change");
sourcepub fn map<Output, Generate>(&self, generate: Generate) -> ReadSignal<Output>where
Output: 'static,
Generate: 'static + Fn(&T) -> Output,
pub fn map<Output, Generate>(&self, generate: Generate) -> ReadSignal<Output>where
Output: 'static,
Generate: 'static + Fn(&T) -> Output,
Map a function onto the inner value to produce a new ReadSignal
.
This only exists to make type inference easier, and just forwards its
arguments to map_to
.
sourcepub fn map_to<Output>(
&self,
receiver: impl SignalReceiver<T, Output>
) -> ReadSignal<Output>where
Output: 'static,
pub fn map_to<Output>(
&self,
receiver: impl SignalReceiver<T, Output>
) -> ReadSignal<Output>where
Output: 'static,
Receive changes to a signal.