optimizations aroud preallocating

packages/core/src/create.rs

@@ -35,6 +35,9 @@ impl<'b> VirtualDom {
 
         let cur_scope = self.scope_stack.last().copied().unwrap();
 
+        // we know that this will generate at least one mutation per node
+        self.mutations.edits.reserve(template.template.roots.len());
+
         let mut on_stack = 0;
         for (root_idx, root) in template.template.roots.iter().enumerate() {
             // We might need to generate an ID for the root node
@@ -207,19 +210,12 @@ impl<'b> VirtualDom {
 
         // If it's all dynamic nodes, then we don't need to register it
         // Quickly run through and see if it's all just dynamic nodes
-        let dynamic_roots = template
-            .template
-            .roots
-            .iter()
-            .filter(|root| {
-                matches!(
-                    root,
-                    TemplateNode::Dynamic(_) | TemplateNode::DynamicText(_)
-                )
-            })
-            .count();
-
-        if dynamic_roots == template.template.roots.len() {
+        if template.template.roots.iter().all(|root| {
+            matches!(
+                root,
+                TemplateNode::Dynamic(_) | TemplateNode::DynamicText(_)
+            )
+        }) {
             return;
         }
 
@@ -290,7 +286,7 @@ impl<'b> VirtualDom {
     }
 
     pub(crate) fn create_fragment(&mut self, nodes: &'b [VNode<'b>]) -> usize {
-        nodes.iter().fold(0, |acc, child| acc + self.create(child))
+        nodes.iter().map(|child| self.create(child)).sum()
     }
 
     pub(super) fn create_component_node(
@@ -301,7 +297,7 @@ impl<'b> VirtualDom {
     ) -> usize {
         let props = component
             .props
-            .replace(None)
+            .take()
             .expect("Props to always exist when a component is being created");
 
         let unbounded_props = unsafe { std::mem::transmute(props) };

packages/core/src/mutations.rs

@@ -1,6 +1,6 @@
 use fxhash::FxHashSet;
 
-use crate::{arena::ElementId, ScopeId, ScopeState, Template};
+use crate::{arena::ElementId, ScopeId, Template};
 
 /// A container for all the relevant steps to modify the Real DOM
 ///
@@ -257,9 +257,3 @@ pub enum Mutation<'a> {
         id: ElementId,
     },
 }
-
-#[test]
-fn sizes() {
-    println!("mutations: {}", std::mem::size_of::<Mutation>());
-    println!("scope: {}", std::mem::size_of::<ScopeState>());
-}

packages/core/src/scope_arena.rs

@@ -9,6 +9,7 @@ use crate::{
     virtual_dom::VirtualDom,
     AttributeValue, DynamicNode, VNode,
 };
+use bumpalo::Bump;
 use futures_util::FutureExt;
 use std::{
     mem,
@@ -94,7 +95,13 @@ impl VirtualDom {
         let mut new_nodes = unsafe {
             let scope = self.scopes[scope_id.0].as_mut();
 
-            scope.previous_frame_mut().bump.reset();
+            // if this frame hasn't been intialized yet, we can guess the size of the next frame to be more efficient
+            if scope.previous_frame().bump.allocated_bytes() == 0 {
+                scope.previous_frame_mut().bump =
+                    Bump::with_capacity(scope.current_frame().bump.allocated_bytes());
+            } else {
+                scope.previous_frame_mut().bump.reset();
+            }
 
             // Make sure to reset the hook counter so we give out hooks in the right order
             scope.hook_idx.set(0);
@@ -160,8 +167,8 @@ impl VirtualDom {
         let frame = scope.previous_frame();
 
         // set the new head of the bump frame
-        let alloced = &*frame.bump.alloc(new_nodes);
-        frame.node.set(alloced);
+        let allocated = &*frame.bump.alloc(new_nodes);
+        frame.node.set(allocated);
 
         // And move the render generation forward by one
         scope.render_cnt.set(scope.render_cnt.get() + 1);
@@ -173,6 +180,6 @@ impl VirtualDom {
         });
 
         // rebind the lifetime now that its stored internally
-        unsafe { mem::transmute(alloced) }
+        unsafe { mem::transmute(allocated) }
     }
 }