Various perf and size improvements (#3704)

* test switch for props

* remove _parentDom from rendererState

* align mount and patch component closer

* revert switch

* optimize commitQueue

* remove rendererState

* make root logic more concicse

src/component.js

@@ -3,20 +3,10 @@ import options from './options';
 import { createVNode, Fragment } from './create-element';
 import { patch } from './diff/patch';
 import { DIRTY_BIT, FORCE_UPDATE, MODE_UNMOUNTING } from './constants';
-import { getParentContext, getParentDom } from './tree';
+import { getParentDom } from './tree';
 
 export let ENABLE_CLASSES = false;
 
-/**
- * The render queue
- * @type {import('./internal').RendererState}
- */
-export const rendererState = {
-	_parentDom: null,
-	_context: {},
-	_commitQueue: []
-};
-
 /**
  * Base Component class. Provides `setState()` and `forceUpdate()`, which
  * trigger rendering
@@ -111,10 +101,7 @@ function rerender(internal) {
 			0
 		);
 
-		rendererState._context = getParentContext(internal);
-		rendererState._commitQueue = [];
-		rendererState._parentDom = getParentDom(internal);
-		patch(internal, vnode);
+		patch(internal, vnode, getParentDom(internal));
 		commitRoot(internal);
 	}
 }

src/create-root.js

@@ -10,7 +10,6 @@ import options from './options';
 import { mount } from './diff/mount';
 import { patch } from './diff/patch';
 import { createInternal } from './tree';
-import { rendererState } from './component';
 
 /**
  *
@@ -30,13 +29,8 @@ export function createRoot(parentDom) {
 		firstChild =
 			/** @type {import('./internal').PreactElement} */ (parentDom.firstChild);
 
-		rendererState._context = {};
-		// List of effects that need to be called after diffing:
-		rendererState._commitQueue = [];
-		rendererState._parentDom = parentDom;
-
 		if (rootInternal) {
-			patch(rootInternal, vnode);
+			patch(rootInternal, vnode, parentDom);
 		} else {
 			rootInternal = createInternal(vnode);
 
@@ -55,7 +49,7 @@ export function createRoot(parentDom) {
 
 			rootInternal._context = {};
 
-			mount(rootInternal, vnode, firstChild);
+			mount(rootInternal, vnode, parentDom, firstChild);
 		}
 
 		// Flush all queued effects

src/diff/children.js

@@ -12,14 +12,14 @@ import { mount } from './mount';
 import { patch } from './patch';
 import { unmount } from './unmount';
 import { createInternal, getDomSibling } from '../tree';
-import { rendererState } from '../component';
 
 /**
  * Update an internal with new children.
  * @param {import('../internal').Internal} internal The internal whose children should be patched
  * @param {import('../internal').ComponentChild[]} children The new children, represented as VNodes
+ * @param {import('../internal').PreactElement} parentDom The element into which this subtree is rendered
  */
-export function patchChildren(internal, children) {
+export function patchChildren(internal, children, parentDom) {
 	let oldChildren =
 		(internal._children && internal._children.slice()) || EMPTY_ARR;
 
@@ -75,6 +75,7 @@ export function patchChildren(internal, children) {
 			mount(
 				childInternal,
 				childVNode,
+				parentDom,
 				getDomSibling(internal, skewedIndex)
 			);
 		}
@@ -85,14 +86,10 @@ export function patchChildren(internal, children) {
 			(MODE_HYDRATE | MODE_SUSPENDED)
 		) {
 			// We are resuming the hydration of a VNode
-			mount(
-				childInternal,
-				childVNode,
-				childInternal._dom
-			);
+			mount(childInternal, childVNode, parentDom, childInternal._dom);
 		} else {
 			// Morph the old element into the new one, but don't append it to the dom yet
-			patch(childInternal, childVNode);
+			patch(childInternal, childVNode, parentDom);
 		}
 
 		go: if (mountingChild) {
@@ -102,7 +99,7 @@ export function patchChildren(internal, children) {
 
 			// Perform insert of new dom
 			if (childInternal.flags & TYPE_DOM) {
-				rendererState._parentDom.insertBefore(
+				parentDom.insertBefore(
 					childInternal._dom,
 					getDomSibling(internal, skewedIndex)
 				);
@@ -136,13 +133,9 @@ export function patchChildren(internal, children) {
 
 			let nextSibling = getDomSibling(internal, skewedIndex + 1);
 			if (childInternal.flags & TYPE_DOM) {
-				rendererState._parentDom.insertBefore(childInternal._dom, nextSibling);
+				parentDom.insertBefore(childInternal._dom, nextSibling);
 			} else {
-				insertComponentDom(
-					childInternal,
-					nextSibling,
-					rendererState._parentDom
-				);
+				insertComponentDom(childInternal, nextSibling, parentDom);
 			}
 		}
 

src/diff/commit.js

@@ -1,21 +1,26 @@
-import { rendererState } from '../component';
 import options from '../options';
 
+/**
+ * A list of components with effects that need to be run at the end of the current render pass.
+ * @type {import('../internal').CommitQueue}
+ */
+export let commitQueue = [];
+
 /**
  * @param {import('../internal').Internal} rootInternal
  */
 export function commitRoot(rootInternal) {
-	let commitQueue = [].concat(rendererState._commitQueue);
-	rendererState._commitQueue = [];
+	let currentQueue = commitQueue;
+	commitQueue = [];
 
-	if (options._commit) options._commit(rootInternal, commitQueue);
+	if (options._commit) options._commit(rootInternal, currentQueue);
 
-	commitQueue.some(internal => {
+	currentQueue.some(internal => {
 		try {
 			// @ts-ignore Reuse the root variable here so the type changes
-			commitQueue = internal._commitCallbacks.length;
+			currentQueue = internal._commitCallbacks.length;
 			// @ts-ignore See above ts-ignore comment
-			while (commitQueue--) {
+			while (currentQueue--) {
 				internal._commitCallbacks.shift()();
 			}
 		} catch (e) {

src/diff/mount.js

@@ -15,17 +15,19 @@ import {
 } from '../constants';
 import { normalizeToVNode, Fragment } from '../create-element';
 import { setProperty } from './props';
-import { createInternal } from '../tree';
+import { createInternal, getParentContext } from '../tree';
 import options from '../options';
-import { ENABLE_CLASSES, rendererState } from '../component';
+import { ENABLE_CLASSES } from '../component';
+import { commitQueue } from './commit';
 /**
  * Diff two virtual nodes and apply proper changes to the DOM
  * @param {import('../internal').Internal} internal The Internal node to mount
  * @param {import('../internal').VNode | string} newVNode The new virtual node
+ * @param {import('../internal').PreactElement} parentDom The element into which this subtree is rendered
  * @param {import('../internal').PreactNode} startDom
  * @returns {import('../internal').PreactNode | null} pointer to the next DOM node to be hydrated (or null)
  */
-export function mount(internal, newVNode, startDom) {
+export function mount(internal, newVNode, parentDom, startDom) {
 	if (options._diff) options._diff(internal, newVNode);
 
 	/** @type {import('../internal').PreactNode} */
@@ -36,29 +38,30 @@ export function mount(internal, newVNode, startDom) {
 			// Root nodes signal that an attempt to render into a specific DOM node on
 			// the page. Root nodes can occur anywhere in the tree and not just at the
 			// top.
-			let prevParentDom = rendererState._parentDom;
-			if (internal.flags & TYPE_ROOT) {
-				rendererState._parentDom = newVNode.props._parentDom;
-
-				// Note: this is likely always true because we are inside mount()
-				if (rendererState._parentDom !== prevParentDom) {
-					prevStartDom = startDom;
-					startDom = null;
-				}
+			if (
+				internal.flags & TYPE_ROOT &&
+				newVNode.props._parentDom !== parentDom
+			) {
+				parentDom = newVNode.props._parentDom;
+				prevStartDom = startDom;
+				startDom = null;
 			}
 
-			let prevContext = rendererState._context;
-
-			nextDomSibling = mountComponent(internal, startDom);
+			const renderResult = mountComponent(internal, startDom);
+			if (renderResult === startDom) {
+				nextDomSibling = startDom;
+			} else {
+				nextDomSibling = mountChildren(
+					internal,
+					renderResult,
+					parentDom,
+					startDom
+				);
+			}
 
 			if (internal._commitCallbacks.length) {
-				rendererState._commitQueue.push(internal);
+				commitQueue.push(internal);
 			}
-
-			rendererState._parentDom = prevParentDom;
-			// In the event this subtree creates a new context for its children, restore
-			// the previous context for its siblings
-			rendererState._context = prevContext;
 		} else {
 			// @TODO: we could just assign this as internal.dom here
 			let hydrateDom =
@@ -192,14 +195,12 @@ function mountElement(internal, dom) {
 				dom.innerHTML = newHtml.__html;
 			}
 		} else if (newChildren != null) {
-			const prevParentDom = rendererState._parentDom;
-			rendererState._parentDom = dom;
 			mountChildren(
 				internal,
 				Array.isArray(newChildren) ? newChildren : [newChildren],
+				dom,
 				isNew ? null : dom.firstChild
 			);
-			rendererState._parentDom = prevParentDom;
 		}
 
 		// (as above, don't diff props during hydration)
@@ -216,9 +217,10 @@ function mountElement(internal, dom) {
  * Mount all children of an Internal
  * @param {import('../internal').Internal} internal The parent Internal of the given children
  * @param {import('../internal').ComponentChild[]} children
+ * @param {import('../internal').PreactElement} parentDom The element into which this subtree is rendered
  * @param {import('../internal').PreactNode} startDom
  */
-export function mountChildren(internal, children, startDom) {
+export function mountChildren(internal, children, parentDom, startDom) {
 	let internalChildren = (internal._children = []),
 		i,
 		childVNode,
@@ -240,7 +242,7 @@ export function mountChildren(internal, children, startDom) {
 		internalChildren[i] = childInternal;
 
 		// Morph the old element into the new one, but don't append it to the dom yet
-		mountedNextChild = mount(childInternal, childVNode, startDom);
+		mountedNextChild = mount(childInternal, childVNode, parentDom, startDom);
 
 		newDom = childInternal._dom;
 
@@ -253,7 +255,7 @@ export function mountChildren(internal, children, startDom) {
 			// The DOM the diff should begin with is now startDom (since we inserted
 			// newDom before startDom) so ignore mountedNextChild and continue with
 			// startDom
-			rendererState._parentDom.insertBefore(newDom, startDom);
+			parentDom.insertBefore(newDom, startDom);
 		}
 
 		if (childInternal.ref) {
@@ -297,13 +299,14 @@ function mountComponent(internal, startDom) {
 
 	// Necessary for createContext api. Setting this property will pass
 	// the context value as `this.context` just for this component.
+	let context = getParentContext(internal);
 	let tmp = type.contextType;
-	let provider = tmp && rendererState._context[tmp._id];
+	let provider = tmp && context[tmp._id];
 	let componentContext = tmp
 		? provider
 			? provider.props.value
 			: tmp._defaultValue
-		: rendererState._context;
+		: context;
 
 	if (provider) provider._subs.add(internal);
 
@@ -379,11 +382,7 @@ function mountComponent(internal, startDom) {
 	c.state = c._nextState;
 
 	if (c.getChildContext != null) {
-		rendererState._context = internal._context = Object.assign(
-			{},
-			rendererState._context,
-			c.getChildContext()
-		);
+		internal._context = Object.assign({}, context, c.getChildContext());
 	}
 
 	if (renderResult == null) {
@@ -401,5 +400,5 @@ function mountComponent(internal, startDom) {
 		renderResult = [renderResult];
 	}
 
-	return mountChildren(internal, renderResult, startDom);
+	return renderResult;
 }