From 60b25e9c2f32fb8524dfbf08c736aaba836aaf06 Mon Sep 17 00:00:00 2001
From: Evan Almloff <evanalmloff@gmail.com>
Date: Fri, 30 Jun 2023 08:54:08 -0700
Subject: [PATCH 1/2] add on unmount hook

---
 packages/hooks/src/lib.rs            |  3 ++
 packages/hooks/src/use_on_unmount.rs | 78 ++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 packages/hooks/src/use_on_unmount.rs

diff --git a/packages/hooks/src/lib.rs b/packages/hooks/src/lib.rs
index 1e718eda3..ff94fec1e 100644
--- a/packages/hooks/src/lib.rs
+++ b/packages/hooks/src/lib.rs
@@ -21,6 +21,9 @@ macro_rules! to_owned {
     )*}
 }
 
+mod use_on_unmount;
+pub use use_on_unmount;
+
 mod usecontext;
 pub use usecontext::*;
 
diff --git a/packages/hooks/src/use_on_unmount.rs b/packages/hooks/src/use_on_unmount.rs
new file mode 100644
index 000000000..528491746
--- /dev/null
+++ b/packages/hooks/src/use_on_unmount.rs
@@ -0,0 +1,78 @@
+/// Creats a callback that will be run before the component is removed. This can be used to clean up side effects from the component (created with use_effect)
+///
+/// Example:
+/// ```rust
+/// use dioxus::prelude::*;
+
+/// fn main() {
+///     dioxus_web::launch(app)
+/// }
+
+/// fn app(cx: Scope) -> Element {
+///     let state = use_state(cx, || true);
+///     render! {
+///         for _ in 0..100 {
+///             h1 {
+///                 "spacer"
+///             }
+///         }
+///         if **state {
+///             render! {
+///                 child_component {}
+///             }
+///         }
+///         button {
+///             onclick: move |_| {
+///                 state.set(!*state.get());
+///             },
+///             "Unmount element"
+///         }
+///     }
+/// }
+
+/// fn child_component(cx: Scope) -> Element {
+///     let original_scroll_position = use_state(cx, || 0.0);
+///     use_effect(cx, (), move |_| {
+///         to_owned![original_scroll_position];
+///         async move {
+///             let window = web_sys::window().unwrap();
+///             let document = window.document().unwrap();
+///             let element = document.get_element_by_id("my_element").unwrap();
+///             element.scroll_into_view();
+///             original_scroll_position.set(window.scroll_y().unwrap());
+///         }
+///     });
+
+///     use_on_unmount(cx, {
+///         to_owned![original_scroll_position];
+///         /// restore scroll to the top of the page
+///         move || {
+///             let window = web_sys::window().unwrap();
+///             window.scroll_with_x_and_y(*original_scroll_position.current(), 0.0);
+///         }
+///     });
+
+///     render!{
+///         div {
+///             id: "my_element",
+///             "hello"
+///         }
+///     }
+/// }
+/// ```
+pub fn use_on_unmount<C: FnOnce() + 'static, D: FnOnce() + 'static>(cx: &ScopeState, destroy: D) {
+    cx.use_hook(|| LifeCycle {
+        ondestroy: Some(destroy),
+    });
+}
+
+struct LifeCycle<D: FnOnce()> {
+    ondestroy: Option<D>,
+}
+
+impl<D: FnOnce()> Drop for LifeCycle<D> {
+    fn drop(&mut self) {
+        let f = self.ondestroy.take().unwrap();
+        f();
+    }
+}

From a6e87cf3400a79f3f1d41a6a3ee45d599a3adc77 Mon Sep 17 00:00:00 2001
From: Evan Almloff <evanalmloff@gmail.com>
Date: Fri, 30 Jun 2023 12:56:22 -0700
Subject: [PATCH 2/2] fix tests

---
 packages/hooks/Cargo.toml            | 1 +
 packages/hooks/src/lib.rs            | 2 +-
 packages/hooks/src/use_on_unmount.rs | 6 +-----
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/packages/hooks/Cargo.toml b/packages/hooks/Cargo.toml
index 19d5e53bd..87adebbe4 100644
--- a/packages/hooks/Cargo.toml
+++ b/packages/hooks/Cargo.toml
@@ -21,3 +21,4 @@ log = { workspace = true }
 futures-util = { workspace = true, default-features = false }
 dioxus-core = { workspace = true }
 dioxus = { workspace = true }
+web-sys = { version = "0.3.64", features = ["Document", "Window", "Element"] }
diff --git a/packages/hooks/src/lib.rs b/packages/hooks/src/lib.rs
index ff94fec1e..de9409650 100644
--- a/packages/hooks/src/lib.rs
+++ b/packages/hooks/src/lib.rs
@@ -22,7 +22,7 @@ macro_rules! to_owned {
 }
 
 mod use_on_unmount;
-pub use use_on_unmount;
+pub use use_on_unmount::*;
 
 mod usecontext;
 pub use usecontext::*;
diff --git a/packages/hooks/src/use_on_unmount.rs b/packages/hooks/src/use_on_unmount.rs
index 528491746..1fa4449c1 100644
--- a/packages/hooks/src/use_on_unmount.rs
+++ b/packages/hooks/src/use_on_unmount.rs
@@ -4,10 +4,6 @@
 /// ```rust
 /// use dioxus::prelude::*;
 
-/// fn main() {
-///     dioxus_web::launch(app)
-/// }
-
 /// fn app(cx: Scope) -> Element {
 ///     let state = use_state(cx, || true);
 ///     render! {
@@ -60,7 +56,7 @@
 ///     }
 /// }
 /// ```
-pub fn use_on_unmount<C: FnOnce() + 'static, D: FnOnce() + 'static>(cx: &ScopeState, destroy: D) {
+pub fn use_on_unmount<D: FnOnce() + 'static>(cx: &dioxus_core::ScopeState, destroy: D) {
     cx.use_hook(|| LifeCycle {
         ondestroy: Some(destroy),
     });