leptos_windowing/loaders/
exact_loader.rs

1use std::{fmt::Debug, ops::Range};
2
3/// Trait for loading items on-demand from an data source that let's you request precise ranges.
4///
5/// Implement this if your data source actually returns exactly the range of items requested and
6/// if it can provide the total number of items.
7pub trait ExactLoader {
8    /// The type of items that will be loaded.
9    type Item;
10
11    /// The type of the query data that will be used to load items.
12    ///
13    /// Can be used to filter or sort the items for example.
14    type Query;
15
16    /// The type of errors that can occur during loading.
17    type Error: Debug + 'static;
18
19    /// Does the actual loading of items.
20    ///
21    /// This will be called with a range respecting the chunk size.
22    /// The query data can be used to filter or sort the items for example.
23    ///
24    /// It returns a list of items. If the number of items is less than the requested range,
25    /// it means that the end of the data source has been reached.
26    fn load_items(
27        &self,
28        range: Range<usize>,
29        query: &Self::Query,
30    ) -> impl Future<Output = Result<Vec<Self::Item>, Self::Error>>;
31
32    /// The total number of items of this data source with respect to the query.
33    ///
34    /// Returns `Ok(None)` if unknown (which is the default).
35    fn item_count(
36        &self,
37        _query: &Self::Query,
38    ) -> impl Future<Output = Result<Option<usize>, Self::Error>> {
39        async move { Ok(None) }
40    }
41}
leptos_windowing/loaders/exact_loader.rs

leptos_windowing/loaders/
exact_loader.rs
