Leptos-Use Guide

sync_signal

Category
Reactivity
Module
leptos_use
Feature
sync_signal

Two-way Signals synchronization.

Note: Please consider first if you can achieve your goals with the "Good Options" described in the Leptos book Only if you really have to, use this function. This is, in effect, the "If you really must..." option.

Demo

source

Usage

use leptos::prelude::*;
use leptos::logging::log;
use leptos_use::sync_signal;

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal(1);
let (b, set_b) = signal(2);

let stop = sync_signal((a, set_a), (b, set_b));

log!("a: {}, b: {}", a.get(), b.get()); // a: 1, b: 1

set_b.set(3);

log!("a: {}, b: {}", a.get(), b.get()); // a: 3, b: 3

set_a.set(4);

log!("a: {}, b: {}", a.get(), b.get()); // a: 4, b: 4

view! { }
}

RwSignal

You can mix and match RwSignals and Signal-WriteSignal pairs.

use leptos::prelude::*;
use leptos_use::sync_signal;

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal(1);
let (b, set_b) = signal(2);
let c_rw = RwSignal::new(3);
let d_rw = RwSignal::new(4);

sync_signal((a, set_a), c_rw);
sync_signal(d_rw, (b, set_b));
sync_signal(c_rw, d_rw);


view! { }
}

One directional

You can synchronize a signal only from left to right or right to left.

use leptos::prelude::*;
use leptos::logging::log;
use leptos_use::{sync_signal_with_options, SyncSignalOptions, SyncDirection};

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal(1);
let (b, set_b) = signal(2);

let stop = sync_signal_with_options(
    (a, set_a),
    (b, set_b),
    SyncSignalOptions::default().direction(SyncDirection::LeftToRight)
);

set_b.set(3); // doesn't sync

log!("a: {}, b: {}", a.get(), b.get()); // a: 1, b: 3

set_a.set(4);

log!("a: {}, b: {}", a.get(), b.get()); // a: 4, b: 4

view! { }
}

Custom Transform

You can optionally provide custom transforms between the two signals.

use leptos::prelude::*;
use leptos::logging::log;
use leptos_use::{sync_signal_with_options, SyncSignalOptions};

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal(10);
let (b, set_b) = signal(2);

let stop = sync_signal_with_options(
    (a, set_a),
    (b, set_b),
    SyncSignalOptions::with_transforms(
        |left| *left * 2,
        |right| *right / 2,
    ),
);

log!("a: {}, b: {}", a.get(), b.get()); // a: 10, b: 20

set_b.set(30);

log!("a: {}, b: {}", a.get(), b.get()); // a: 15, b: 30

view! { }
}

Different Types

SyncSignalOptions::default() is only defined if the two signal types are identical. Otherwise, you have to initialize the options with with_transforms or with_assigns instead of default.

use leptos::prelude::*;
use leptos_use::{sync_signal_with_options, SyncSignalOptions};
use std::str::FromStr;

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal("10".to_string());
let (b, set_b) = signal(2);

let stop = sync_signal_with_options(
    (a, set_a),
    (b, set_b),
    SyncSignalOptions::with_transforms(
        |left: &String| i32::from_str(left).unwrap_or_default(),
        |right: &i32| right.to_string(),
    ),
);

view! { }
}
use leptos::prelude::*;
use leptos_use::{sync_signal_with_options, SyncSignalOptions};
use std::str::FromStr;

#[derive(Clone)]
pub struct Foo {
    bar: i32,
}

#[component]
fn Demo() -> impl IntoView {
let (a, set_a) = signal(Foo { bar: 10 });
let (b, set_b) = signal(2);

let stop = sync_signal_with_options(
    (a, set_a),
    (b, set_b),
    SyncSignalOptions::with_assigns(
        |b: &mut i32, a: &Foo| *b = a.bar,
        |a: &mut Foo, b: &i32| a.bar = *b,
    ),
);

view! { }
}

Feature

This function is only available if the crate feature sync_signal is enabled

Types

Source

Source • Demo • Docs