Struct StorageEntry 

pub struct StorageEntry<S: StorageBacking, T: Serialize + DeserializeOwned + Clone + Send + Sync + 'static> { /* private fields */ }

A storage entry that can be used to store data across application reloads. It optionally provides a channel to subscribe to updates to the underlying storage.

Implementations

impl<S, T> StorageEntry<S, T>

where S: StorageBacking, T: Serialize + DeserializeOwned + Clone + Send + Sync + 'static, S::Key: Clone,

pub fn new(key: S::Key, data: T) -> Self

Creates a new StorageEntry

Methods from Deref<Target = Signal<T>>

pub fn point_to(&self, other: Signal<T, S>) -> Result<(), BorrowError>

where T: 'static,

Point to another signal. This will subscribe the other signal to all subscribers of this signal.

pub fn manually_drop(&self)

where T: 'static,

Drop the value out of the signal, invalidating the signal in the process.

pub fn origin_scope(&self) -> ScopeId

Get the scope the signal was created in.

pub fn id(&self) -> GenerationalBoxId

Get the generational id of the signal.

pub fn write_silent(&self) -> WriteLock<'static, T, S>

👎Deprecated: This pattern is no longer recommended. Prefer peek or creating new signals instead.

This pattern is no longer recommended. Prefer peek or creating new signals instead.

This function is the equivalent of the write_silent method on use_ref.

What you should use instead

Reading and Writing to data in the same scope

Reading and writing to the same signal in the same scope will cause that scope to rerun forever:

let mut signal = use_signal(|| 0);
// This makes the scope rerun whenever we write to the signal
println!("{}", *signal.read());
// This will rerun the scope because we read the signal earlier in the same scope
*signal.write() += 1;

You may have used the write_silent method to avoid this infinite loop with use_ref like this:

let signal = use_signal(|| 0);
// This makes the scope rerun whenever we write to the signal
println!("{}", *signal.read());
// Write silent will not rerun any subscribers
*signal.write_silent() += 1;

Instead you can use the peek and write methods instead. The peek method will not subscribe to the current scope which will avoid an infinite loop if you are reading and writing to the same signal in the same scope.

let mut signal = use_signal(|| 0);
// Peek will read the value but not subscribe to the current scope
println!("{}", *signal.peek());
// Write will update any subscribers which does not include the current scope
*signal.write() += 1;

Reading and Writing to different data

Why is this pattern no longer recommended?

This pattern is no longer recommended because it is very easy to allow your state and UI to grow out of sync. write_silent globally opts out of automatic state updates which can be difficult to reason about.

Lets take a look at an example: main.rs:

fn app() -> Element {
    let signal = use_context_provider(|| Signal::new(0));

    // We want to log the value of the signal whenever the app component reruns
    println!("{}", *signal.read());

    rsx! {
        button {
            // If we don't want to rerun the app component when the button is clicked, we can use write_silent
            onclick: move |_| *signal.write_silent() += 1,
            "Increment"
        }
        Child {}
    }
}

child.rs:

fn Child() -> Element {
    let signal: Signal<i32> = use_context();

    // It is difficult to tell that changing the button to use write_silent in the main.rs file will cause UI to be out of sync in a completely different file
    rsx! {
        "{signal}"
    }
}

Instead peek locally opts out of automatic state updates explicitly for a specific read which is easier to reason about.

Here is the same example using peek: main.rs:

fn app() -> Element {
    let mut signal = use_context_provider(|| Signal::new(0));

    // We want to log the value of the signal whenever the app component reruns, but we don't want to rerun the app component when the signal is updated so we use peek instead of read
    println!("{}", *signal.peek());

    rsx! {
        button {
            // We can use write like normal and update the child component automatically
            onclick: move |_| *signal.write() += 1,
            "Increment"
        }
        Child {}
    }
}

child.rs:

fn Child() -> Element {
    let signal: Signal<i32> = use_context();

    rsx! {
        "{signal}"
    }
}

Trait Implementations

impl<S: Clone + StorageBacking, T: Clone + Serialize + DeserializeOwned + Clone + Send + Sync + 'static> Clone for StorageEntry<S, T>

where S::Key: Clone,

fn clone(&self) -> StorageEntry<S, T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S: StorageBacking, T: Debug + Serialize + DeserializeOwned + Clone + Send + Sync> Debug for StorageEntry<S, T>

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

Formats the value using the given formatter.

impl<S: StorageBacking, T: Serialize + DeserializeOwned + Clone + Send + Sync> Deref for StorageEntry<S, T>

type Target = Signal<T>

The resulting type after dereferencing.

fn deref(&self) -> &Signal<T>

Dereferences the value.

impl<S: StorageBacking, T: Serialize + DeserializeOwned + Clone + Send + Sync> DerefMut for StorageEntry<S, T>

fn deref_mut(&mut self) -> &mut Signal<T>

Mutably dereferences the value.

impl<S: StorageBacking, T: Display + Serialize + DeserializeOwned + Clone + Send + Sync> Display for StorageEntry<S, T>

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

Formats the value using the given formatter.

impl<S, T> StorageEntryTrait<S, T> for StorageEntry<S, T>

where S: StorageBacking, T: Serialize + DeserializeOwned + Clone + PartialEq + Send + Sync + 'static,

fn save(&self)

Saves the current state to storage

fn update(&mut self)

Updates the state from storage

fn key(&self) -> &S::Key

Gets the key used to store the data in storage

fn data(&self) -> &Signal<T>

Gets the signal that can be used to read and modify the state

fn save_to_storage_on_change(&self)

where S: StorageBacking, T: Serialize + DeserializeOwned + Clone + PartialEq + 'static,

Creates a hook that will save the state to storage when the state changes