Add a method to emit multiple messages in one callback (yewstack#660)

* feat: add create_effect method to help create effect callback

* style: fmt code with rustfmt

* feat: support bunch update in one render loop

* typo: change bunch to batch

* style: fmt with cargo

src/html/mod.rs

@@ -224,6 +224,19 @@ where
         }
     }
 
+    /// This method sends batch of messages back to the component's loop
+    pub fn send_back_batch<F, IN>(&mut self, function: F) -> Callback<IN>
+    where
+        F: Fn(IN) -> Vec<COMP::Message> + 'static,
+    {
+        let scope = self.scope.clone();
+        let closure = move |input| {
+            let messages = function(input);
+            scope.clone().send_message_batch(messages);
+        };
+        closure.into()
+    }
+
     /// This method sends messages back to the component's loop.
     pub fn send_back<F, IN>(&mut self, function: F) -> Callback<IN>
     where

src/html/scope.rs

@@ -13,6 +13,8 @@ pub type NodeCell = Rc<RefCell<Option<Node>>>;
 pub(crate) enum ComponentUpdate<COMP: Component> {
     /// Wraps messages for a component.
     Message(COMP::Message),
+    /// Wraps batch of messages for a component.
+    MessageBatch(Vec<COMP::Message>),
     /// Wraps properties for a component.
     Properties(COMP::Properties),
 }
@@ -59,6 +61,11 @@ where
     pub fn send_message(&mut self, msg: COMP::Message) {
         self.update(ComponentUpdate::Message(msg));
     }
+
+    /// send batch of messages to the component
+    pub fn send_message_batch(&mut self, messages: Vec<COMP::Message>) {
+        self.update(ComponentUpdate::MessageBatch(messages));
+    }
 }
 
 enum ComponentState<COMP: Component> {
@@ -249,7 +256,10 @@ where
         self.shared_state.replace(match current_state {
             ComponentState::Created(mut this) => {
                 let should_update = match self.update {
-                    ComponentUpdate::Message(msg) => this.component.update(msg),
+                    ComponentUpdate::Message(message) => this.component.update(message),
+                    ComponentUpdate::MessageBatch(messages) => messages
+                        .into_iter()
+                        .fold(false, |acc, msg| this.component.update(msg) || acc),
                     ComponentUpdate::Properties(props) => this.component.change(props),
                 };
                 let next_state = if should_update { this.update() } else { this };