Rename modules to use snake_case (#1498)

packages/hooks/src/use_memo.rs

@@ -0,0 +1,46 @@
+use dioxus_core::ScopeState;
+
+use crate::UseFutureDep;
+
+/// A hook that provides a callback that executes if the dependencies change.
+/// This is useful to avoid running computation-expensive calculations even when the data doesn't change.
+///
+/// - dependencies: a tuple of references to values that are `PartialEq` + `Clone`
+///
+/// ## Examples
+///
+/// ```rust, no_run
+/// # use dioxus::prelude::*;
+///
+/// #[component]
+/// fn Calculator(cx: Scope, number: usize) -> Element {
+///     let bigger_number = use_memo(cx, (number,), |(number,)| {
+///         // This will only be calculated when `number` has changed.
+///         number * 100
+///     });
+///     render!(
+///         p { "{bigger_number}" }
+///     )
+/// }
+///
+/// #[component]
+/// fn App(cx: Scope) -> Element {
+///     render!(Calculator { number: 0 })
+/// }
+/// ```
+pub fn use_memo<T, D>(cx: &ScopeState, dependencies: D, callback: impl FnOnce(D::Out) -> T) -> &T
+where
+    T: 'static,
+    D: UseFutureDep,
+{
+    let value = cx.use_hook(|| None);
+
+    let dependancies_vec = cx.use_hook(Vec::new);
+
+    if dependencies.clone().apply(dependancies_vec) || value.is_none() {
+        // Create the new value
+        *value = Some(callback(dependencies.out()));
+    }
+
+    value.as_ref().unwrap()
+}