add use_infinite_scroll (#12)

README.md

@@ -126,6 +126,7 @@ fn counter() -> Html {
 - `use_window_scroll` - tracks Window scroll position.
 - `use_scroll` - tracks an HTML element's scroll position.
 - `use_scrolling` - tracks whether HTML element is scrolling.
+- `use_infinite_scroll` - infinite scrolling of the element.
 - `use_location` - tracks brower's location value.
 - `use_hash` - tracks brower's location hash value.
 - `use_search_param` - tracks brower's location search param value.

crates/yew-hooks/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "yew-hooks"
-version = "0.1.54"
+version = "0.1.55"
 edition = "2018"
 authors = ["Jet Li <jing.i.qin@icloud.com>"]
 categories = ["gui", "wasm", "web-programming"]

crates/yew-hooks/src/hooks/mod.rs

@@ -15,6 +15,7 @@ mod use_event;
 mod use_favicon;
 mod use_geolocation;
 mod use_hash;
+mod use_infinite_scroll;
 mod use_interval;
 mod use_is_first_mount;
 mod use_is_mounted;
@@ -69,6 +70,7 @@ pub use use_event::*;
 pub use use_favicon::*;
 pub use use_geolocation::*;
 pub use use_hash::*;
+pub use use_infinite_scroll::*;
 pub use use_interval::*;
 pub use use_is_first_mount::*;
 pub use use_is_mounted::*;

crates/yew-hooks/src/hooks/use_infinite_scroll.rs

@@ -0,0 +1,79 @@
+use web_sys::Element;
+use yew::prelude::*;
+
+use super::{use_debounce, use_event, use_latest};
+
+/// A sensor hook that tracks infinite scrolling of the element.
+///
+/// # Example
+///
+/// ```rust
+/// # use yew::prelude::*;
+/// #
+/// use yew_hooks::{use_infinite_scroll, use_list};
+///
+/// #[function_component(UseInfiniteScroll)]
+/// fn infinite_scroll() -> Html {
+///     let node = use_node_ref();
+///     let state = use_list(vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+///
+///     {
+///         let state = state.clone();
+///         use_infinite_scroll(node.clone(), move || {
+///             let max = state.current().len() + 1;
+///             let mut more = vec![max, max + 1, max + 2, max + 3, max + 4];
+///             state.append(&mut more);
+///         });
+///     }
+///
+///     html! {
+///         <div ref={node}>
+///             {
+///                 for state.current().iter().map(|element| {
+///                     html! { <p>{ element }</p> }
+///                 })
+///             }
+///         </div>
+///     }
+/// }
+/// ```
+pub fn use_infinite_scroll<Callback>(node: NodeRef, callback: Callback)
+where
+    Callback: Fn() + 'static,
+{
+    let callback_ref = use_latest(callback);
+    let load_more = use_state_eq(|| false);
+
+    {
+        let load_more = load_more.clone();
+        use_effect_with_deps(
+            move |load_more| {
+                if **load_more {
+                    let callback = &*callback_ref.current();
+                    callback();
+                }
+
+                || ()
+            },
+            load_more,
+        );
+    }
+
+    let debounce = {
+        let load_more = load_more.clone();
+        use_debounce(
+            move || {
+                load_more.set(false);
+            },
+            150,
+        )
+    };
+
+    use_event(node, "scroll", move |e: Event| {
+        let element: Element = e.target_unchecked_into();
+        if element.scroll_height() - element.scroll_top() <= element.client_height() {
+            load_more.set(true);
+            debounce.run();
+        }
+    });
+}

crates/yew-hooks/src/hooks/use_scrolling.rs

@@ -1,7 +1,6 @@
-use gloo::timers::callback::Timeout;
 use yew::prelude::*;
 
-use super::{use_event, use_unmount};
+use super::{use_debounce, use_event};
 
 /// A sensor hook that tracks whether HTML element is scrolling.
 ///
@@ -26,24 +25,25 @@ use super::{use_event, use_unmount};
 /// }
 /// ```
 pub fn use_scrolling(node: NodeRef) -> bool {
-    let state = use_state(|| false);
-    let timer = use_mut_ref(|| None);
+    let state = use_state_eq(|| false);
+
+    let debounce = {
+        let state = state.clone();
+        use_debounce(
+            move || {
+                state.set(false);
+            },
+            150,
+        )
+    };
 
     {
         let state = state.clone();
-        let timer = timer.clone();
         use_event(node, "scroll", move |_: Event| {
             state.set(true);
-            let state = state.clone();
-            *timer.borrow_mut() = Some(Timeout::new(150, move || {
-                state.set(false);
-            }));
+            debounce.run();
         });
     }
 
-    use_unmount(move || {
-        *timer.borrow_mut() = None;
-    });
-
     *state
 }

examples/yew-app/src/routes/home.rs

@@ -25,7 +25,7 @@ pub fn home() -> Html {
                         <li><Link<AppRoute> to={AppRoute::UseSet} classes="app-link">{ "use_set" }</Link<AppRoute>> { " - tracks state of a hash set." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseQueue} classes="app-link">{ "use_queue" }</Link<AppRoute>> { " - tracks state of a queue." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseRafState} classes="app-link">{ "use_raf_state" }</Link<AppRoute>> { " - creates set method which only updates after requestAnimationFrame." }</li>
-                        <li><Link<AppRoute> to={AppRoute::UseStatePtrEq} classes="app-link">{ "use_state_ptr_eq" }</Link<AppRoute>> { " - similar to use_state_eq, but checks if the two Rcs of values point to the same allocation." }</li>
+                        <li><Link<AppRoute> to={AppRoute::UseStatePtrEq} classes="app-link">{ "use_state_ptr_eq" }</Link<AppRoute>> { " - similar to use_state_eq, but checks two Rcs' pointers of allocation." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseRendersCount} classes="app-link">{ "use_renders_count" }</Link<AppRoute>> { " - counts component renders." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseDefault} classes="app-link">{ "use_default" }</Link<AppRoute>> { " - returns the default value when state is None." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseDebounceState} classes="app-link">{ "use_debounce_state" }</Link<AppRoute>> { " - debounces state." }</li>
@@ -78,6 +78,7 @@ pub fn home() -> Html {
                         <li><Link<AppRoute> to={AppRoute::UseWindowScroll} classes="app-link" >{ "use_window_scroll" }</Link<AppRoute>> { " - tracks Window scroll position." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseScroll} classes="app-link" >{ "use_scroll" }</Link<AppRoute>> { " - tracks an HTML element's scroll position." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseScrolling} classes="app-link" >{ "use_scrolling" }</Link<AppRoute>> { " - tracks whether HTML element is scrolling." }</li>
+                        <li><Link<AppRoute> to={AppRoute::UseInfiniteScroll} classes="app-link" >{ "use_infinite_scroll" }</Link<AppRoute>> { " - infinite scrolling of the element." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseLocation} classes="app-link" >{ "use_location" }</Link<AppRoute>> { " - tracks brower's location value." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseHash} classes="app-link" >{ "use_hash" }</Link<AppRoute>> { " - tracks brower's location hash value." }</li>
                         <li><Link<AppRoute> to={AppRoute::UseSearchParam} classes="app-link" >{ "use_search_param" }</Link<AppRoute>> { " - tracks brower's location search param value." }</li>

examples/yew-app/src/routes/hooks/mod.rs

@@ -16,6 +16,7 @@ mod use_event;
 mod use_favicon;
 mod use_geolocation;
 mod use_hash;
+mod use_infinite_scroll;
 mod use_interval;
 mod use_is_first_mount;
 mod use_is_mounted;
@@ -72,6 +73,7 @@ pub use use_event::*;
 pub use use_favicon::*;
 pub use use_geolocation::*;
 pub use use_hash::*;
+pub use use_infinite_scroll::*;
 pub use use_interval::*;
 pub use use_is_first_mount::*;
 pub use use_is_mounted::*;

examples/yew-app/src/routes/hooks/use_infinite_scroll.rs

@@ -0,0 +1,39 @@
+use yew::prelude::*;
+
+use yew_hooks::{use_infinite_scroll, use_list};
+
+/// `use_infinite_scroll` demo
+#[function_component(UseInfiniteScroll)]
+pub fn infinite_scroll() -> Html {
+    let node = use_node_ref();
+    let state = use_list(vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+
+    {
+        let state = state.clone();
+        use_infinite_scroll(node.clone(), move || {
+            let max = state.current().len() + 1;
+            let mut more = vec![max, max + 1, max + 2, max + 3, max + 4];
+            state.append(&mut more);
+        });
+    }
+
+    html! {
+        <div class="app">
+            <header class="app-header">
+                <div>
+                    <div ref={node} style="width: 600px; height:300px; overflow: scroll; background-color: #61dafb;">
+                        <div>
+                            { "Try to scroll in this area vertically." }
+                            {
+                                for state.current().iter().map(|element| {
+                                    html! { <p style="height: 50px;">{ element }</p> }
+                                })
+                            }
+
+                        </div>
+                    </div>
+                </div>
+            </header>
+        </div>
+    }
+}

examples/yew-app/src/routes/mod.rs

@@ -124,6 +124,8 @@ pub enum AppRoute {
     UseFavicon,
     #[at("/use_clipboard")]
     UseClipboard,
+    #[at("/use_infinite_scroll")]
+    UseInfiniteScroll,
     #[not_found]
     #[at("/page-not-found")]
     PageNotFound,
@@ -191,6 +193,7 @@ pub fn switch(routes: &AppRoute) -> Html {
         AppRoute::UseThrottleEffect => html! { <UseThrottleEffect /> },
         AppRoute::UseFavicon => html! { <UseFavicon /> },
         AppRoute::UseClipboard => html! { <UseClipboard /> },
+        AppRoute::UseInfiniteScroll => html! { <UseInfiniteScroll /> },
         AppRoute::PageNotFound => html! { <Home /> },
     }
 }