Struct MutationContext 

pub struct MutationContext<'a, Data, Error> { /* private fields */ }

Provides access to cached mutation data for implementations generated by the macro.

Implementations

impl<'a, Data, Error> MutationContext<'a, Data, Error>

pub fn new(current: Option<&'a Result<Data, Error>>) -> Self

Create a new mutation context from the current cached result.

pub fn current(&self) -> Option<&Result<Data, Error>>

Returns the current cached result, including the error if the cache failed previously.

pub fn current_success(&self) -> Option<&Data>

Returns a reference to the current successful cached data, if available.

pub fn cloned_success(&self) -> Option<Data>

where Data: Clone,

Clones the current successful cached data, if available.

pub fn map_current<F>(&self, f: F) -> Option<Data>

where Data: Clone, F: FnOnce(&mut Data),

Applies a transformation to the cloned cached data and returns the updated value.

pub fn map_or_else<F, D>(&self, default: D, f: F) -> Data

where Data: Clone, F: FnOnce(&mut Data), D: FnOnce() -> Data,

Applies a transformation to the cloned cached data, or returns a default value if no data is available.

This is useful when you need to ensure a value is always returned, even if the cache is empty.

Example

use dioxus_provider::prelude::*;

#[mutation(invalidates = [fetch_items])]
async fn add_item(
    item: String,
    ctx: MutationContext<Vec<String>, String>,
) -> Result<Vec<String>, String> {
    Ok(ctx.map_or_else(
        || vec![item.clone()],  // default if no cached data
        |items| {
            items.push(item.clone());
        }
    ))
}

pub fn update_in_place<F>(&self, f: F) -> Option<Data>

where Data: Clone, F: FnOnce(&mut Data),

Updates the cached data in place, returning the modified data or None if no data exists.

This is similar to map_current but provides a more explicit name for mutations that modify existing data.

Example

use dioxus_provider::prelude::*;

#[mutation(invalidates = [fetch_counter])]
async fn increment_counter(
    ctx: MutationContext<i32, String>,
) -> Result<i32, String> {
    ctx.update_in_place(|count| *count += 1)
        .ok_or_else(|| "No counter data available".to_string())
}

pub fn has_data(&self) -> bool

Returns true if there is currently cached data available.

pub fn has_error(&self) -> bool

Returns true if the current cache contains an error.