add props safety example

examples/props_safety.rs

@@ -0,0 +1,68 @@
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus_desktop::launch(app);
+}
+
+fn app(cx: Scope) -> Element {
+    let count: &RefCell<Vec<&Element>> = cx.use_hook(|| RefCell::new(Vec::new()));
+
+    let element = render! {
+        div {
+            "hello world!"
+        }
+    };
+
+    let nested_borrows = cx.use_hook(Vec::new);
+    nested_borrows.push("hello world!");
+
+    cx.render(rsx! {
+        // unsafe_child_component {
+        //     borrowed: count
+        // }
+        safe_child_component {
+            borrowed: element
+        }
+        safe_nested_borrows {
+            borrowed: &**nested_borrows
+        }
+    })
+}
+
+#[derive(Props)]
+struct NestedBorrows<'a> {
+    borrowed: &'a [&'a str],
+}
+
+fn safe_nested_borrows<'a>(cx: Scope<'a, NestedBorrows<'a>>) -> Element<'a> {
+    render! {
+        div { "{cx.props.borrowed:?}" }
+    }
+}
+
+#[derive(Props)]
+struct Testing<'a> {
+    borrowed: &'a RefCell<Vec<&'a Element<'a>>>,
+}
+
+fn unsafe_child_component<'a>(cx: Scope<'a, Testing<'a>>) -> Element<'a> {
+    let Testing { borrowed } = cx.props;
+    let borrowed = borrowed.borrow();
+    cx.render(rsx! {
+        div { "Hello, world!" }
+    })
+}
+
+#[derive(Props)]
+struct SafeTesting<'a> {
+    borrowed: Element<'a>,
+}
+
+fn safe_child_component<'a>(cx: Scope<'a, SafeTesting<'a>>) -> Element<'a> {
+    let SafeTesting { borrowed } = cx.props;
+    cx.render(rsx! {
+        div {
+            borrowed
+        }
+    })
+}