Merge branch 'master' into fix/custom_el_diff

Author: David-OConnor

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Added method `El::is_custom(&self)`.
 - Fixed custom elements patching (#325).
+- Implemented `UpdateEl` for `Filter` and `FilterMap`.
 
 ## v0.5.1
 - [BREAKING] `MessageMapper::map_message` changed to `MessageMapper::map_msg`.

examples/todomvc/src/lib.rs

@@ -295,7 +295,7 @@ fn view(model: &Model) -> impl View<Msg> {
     // We use the item's position in model.todos to identify it, because this allows
     // simple in-place modification through indexing. This is different from its
     // position in visible todos, hence the two-step process.
-    let todo_els: Vec<Node<Msg>> = model
+    let todo_els = model
         .todos
         .clone()
         .into_iter()
@@ -306,8 +306,7 @@ fn view(model: &Model) -> impl View<Msg> {
             } else {
                 None
             }
-        })
-        .collect();
+        });
 
     let main = if model.todos.is_empty() {
         seed::empty()

src/virtual_dom/update_el.rs

@@ -95,12 +95,25 @@ impl<Ms> UpdateEl<El<Ms>> for WillUnmount<Ms> {
 }
 
 impl<Ms> UpdateEl<El<Ms>> for &str {
-    // This, or some other mechanism seems to work for String too... note sure why.
     fn update(self, el: &mut El<Ms>) {
         el.children.push(Node::Text(Text::new(self.to_string())))
     }
 }
 
+// In the most cases `&str` is enough,
+// but if we have, for instance, `Filter` iterator of `String`s -
+// then the Rust type system can't coerce `String` to `&str`.
+//
+// However if we implement `UpdateEl` for `String`, code like `h1![model.title]` cannot be compiled,
+// because Rust chooses `String` impl instead of `&str` and fails on moving value (`title`).
+// @TODO How to resolve it? `&self`?
+//
+//impl<Ms> UpdateEl<El<Ms>> for String {
+//    fn update(self, el: &mut El<Ms>) {
+//        el.children.push(Node::Text(Text::new(self)))
+//    }
+//}
+
 impl<Ms> UpdateEl<El<Ms>> for El<Ms> {
     fn update(self, el: &mut El<Ms>) {
         el.children.push(Node::Element(self))
@@ -133,6 +146,8 @@ impl<Ms> UpdateEl<El<Ms>> for Tag {
     }
 }
 
+// ----- Iterators ------
+
 impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::Map<I, F>
 where
     I: Iterator,
@@ -144,57 +159,24 @@ where
     }
 }
 
-// impl<Ms, I, U, P> UpdateEl<El<Ms>> for std::iter::Filter<I, P>
-// where
-//     I: Iterator,
-//     U: UpdateEl<El<Ms>>,
-//     P: FnMut(&I::Item) -> bool,
-// {
-//     fn update(self, el: &mut El<Ms>) {
-//         self.for_each(|item| item.update(el));
-//     }
-// }
-
-//impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::Map<I, F>
-//where
-//    I: Iterator,
-//    U: UpdateEl<Attrs>,
-//    F: FnMut(I::Item) -> U,
-//{
-//    fn update(self, el: &mut El<Ms>) {
-//        self.for_each(|item| item.update(el));
-//    }
-//}
-//
-//impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::Map<I, F>
-//where
-//    I: Iterator,
-//    U: UpdateEl<&Attrs>,
-//    F: FnMut(I::Item) -> U,
-//{
-//    fn update(self, el: &mut El<Ms>) {
-//        self.for_each(|item| item.update(el));
-//    }
-//}
-//
-//impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::Map<I, F>
-//where
-//    I: Iterator,
-//    U: UpdateEl<Style>,
-//    F: FnMut(I::Item) -> U,
-//{
-//    fn update(self, el: &mut El<Ms>) {
-//        self.for_each(|item| item.update(el));
-//    }
-//}
-//
-//impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::Map<I, F>
-//where
-//    I: Iterator,
-//    U: UpdateEl<&Style>,
-//    F: FnMut(I::Item) -> U,
-//{
-//    fn update(self, el: &mut El<Ms>) {
-//        self.for_each(|item| item.update(el));
-//    }
-//}
+impl<Ms, I, U, F> UpdateEl<El<Ms>> for std::iter::FilterMap<I, F>
+where
+    I: Iterator,
+    U: UpdateEl<El<Ms>>,
+    F: FnMut(I::Item) -> Option<U>,
+{
+    fn update(self, el: &mut El<Ms>) {
+        self.for_each(|item| item.update(el));
+    }
+}
+
+impl<Ms, I, U, P> UpdateEl<El<Ms>> for std::iter::Filter<I, P>
+where
+    U: UpdateEl<El<Ms>>,
+    I: Iterator<Item = U>,
+    P: FnMut(&I::Item) -> bool,
+{
+    fn update(self, el: &mut El<Ms>) {
+        self.for_each(|item| item.update(el));
+    }
+}