(core) - map old VNodes to new ones (#236)

* mapping of old nodes

* add changset

.changeset/weak-rules-sparkle.md

@@ -0,0 +1,5 @@
+---
+'@prefresh/core': minor
+---
+
+Update oldVnodeTypes in place with newer equivalents

packages/core/src/index.js

@@ -19,7 +19,7 @@ import {
 	HOOK_CLEANUP
 } from './constants';
 import { computeKey } from './computeKey';
-import { vnodesForComponent } from './runtime/vnodesForComponent';
+import { vnodesForComponent, mappedVNodes } from './runtime/vnodesForComponent';
 import { signaturesForType } from './runtime/signaturesForType';
 
 let typesById = new Map();
@@ -51,6 +51,8 @@ function replaceComponent(OldType, NewType, resetHookState) {
 	vnodesForComponent.delete(OldType);
 	vnodesForComponent.set(NewType, vnodes);
 
+	mappedVNodes.set(OldType, NewType);
+
 	pendingUpdates = pendingUpdates.filter(p => p[0] !== OldType);
 
 	vnodes.forEach(vnode => {

packages/core/src/runtime/vnode.js

@@ -1,5 +1,14 @@
 import { options } from 'preact';
-import { vnodesForComponent } from './vnodesForComponent';
+import { vnodesForComponent, mappedVNodes } from './vnodesForComponent';
+import { VNODE_COMPONENT } from '../constants';
+
+const getMappedVnode = type => {
+	if (mappedVNodes.has(type)) {
+		return getMappedVnode(mappedVNodes.get(type));
+	}
+
+	return type;
+};
 
 const oldVnode = options.vnode;
 options.vnode = vnode => {
@@ -10,6 +19,12 @@ options.vnode = vnode => {
 		} else {
 			vnodes.push(vnode);
 		}
+
+		const foundType = getMappedVnode(vnode.type);
+		vnode.type = foundType;
+		if (vnode[VNODE_COMPONENT]) {
+			vnode[VNODE_COMPONENT].constructor = foundType;
+		}
 	}
 
 	if (oldVnode) oldVnode(vnode);

packages/core/src/runtime/vnodesForComponent.js

@@ -1,2 +1,3 @@
 // all vnodes referencing a given constructor
 export const vnodesForComponent = new WeakMap();
+export const mappedVNodes = new WeakMap();