feat: lightweight react-reconciler-compatible reconciler

packages/bippy/package.json

@@ -57,6 +57,26 @@
         "default": "./dist/install-hook-only.cjs"
       }
     },
+    "./nil": {
+      "import": {
+        "types": "./dist/nil.d.ts",
+        "default": "./dist/nil.js"
+      },
+      "require": {
+        "types": "./dist/nil.d.cts",
+        "default": "./dist/nil.cjs"
+      }
+    },
+    "./reconciler": {
+      "import": {
+        "types": "./dist/reconciler.d.ts",
+        "default": "./dist/reconciler.js"
+      },
+      "require": {
+        "types": "./dist/reconciler.d.cts",
+        "default": "./dist/reconciler.cjs"
+      }
+    },
     "./source": {
       "import": {
         "types": "./dist/source.d.ts",

packages/bippy/src/nil/index.ts

@@ -0,0 +1,104 @@
+import type * as React from "react";
+import { createReconciler } from "../reconciler/index.js";
+import type { ReconcilerRoot } from "../reconciler/index.js";
+
+export { act, flushSyncWork, startTransition } from "../reconciler/index.js";
+
+export interface NilNode<P = Record<string, unknown>> {
+  type: string;
+  props: P;
+  children: NilNode[];
+}
+
+export interface NilContainer {
+  head: NilNode | null;
+  children: NilNode[];
+}
+
+const removeFromChildren = (children: NilNode[], child: NilNode): void => {
+  const childIndex = children.indexOf(child);
+  if (childIndex !== -1) children.splice(childIndex, 1);
+};
+
+const insertIntoChildren = (children: NilNode[], child: NilNode, beforeChild: NilNode): void => {
+  removeFromChildren(children, child);
+  const beforeIndex = children.indexOf(beforeChild);
+  children.splice(beforeIndex === -1 ? children.length : beforeIndex, 0, child);
+};
+
+const nilReconciler = createReconciler({
+  createInstance: (type, props) => ({
+    type: String(type),
+    props,
+    children: [],
+  }),
+  createTextInstance: (text) => ({
+    type: "text",
+    props: { text },
+    children: [],
+  }),
+  finalizeInitialChildren: () => false,
+  getPublicInstance: (instance) => instance,
+  appendChild: (parent: NilNode, child: NilNode) => {
+    removeFromChildren(parent.children, child);
+    parent.children.push(child);
+  },
+  appendInitialChild: (parent: NilNode, child: NilNode) => {
+    removeFromChildren(parent.children, child);
+    parent.children.push(child);
+  },
+  appendChildToContainer: (container: NilContainer, child: NilNode) => {
+    removeFromChildren(container.children, child);
+    container.children.push(child);
+    container.head = container.children[0] ?? null;
+  },
+  insertBefore: (parent: NilNode, child: NilNode, beforeChild: NilNode) => {
+    insertIntoChildren(parent.children, child, beforeChild);
+  },
+  insertInContainerBefore: (container: NilContainer, child: NilNode, beforeChild: NilNode) => {
+    insertIntoChildren(container.children, child, beforeChild);
+    container.head = container.children[0] ?? null;
+  },
+  removeChild: (parent: NilNode, child: NilNode) => {
+    removeFromChildren(parent.children, child);
+  },
+  removeChildFromContainer: (container: NilContainer, child: NilNode) => {
+    removeFromChildren(container.children, child);
+    container.head = container.children[0] ?? null;
+  },
+  clearContainer: (container: NilContainer) => {
+    container.children.length = 0;
+    container.head = null;
+  },
+  commitTextUpdate: (textInstance: NilNode, _oldText, newText) => {
+    textInstance.props = { text: newText };
+  },
+  commitUpdate: (instance: NilNode, _type, _prevProps, nextProps: Record<string, unknown>) => {
+    instance.props = nextProps;
+  },
+});
+
+const containerRoots = new Map<NilContainer, ReconcilerRoot>();
+
+export const render = (element: React.ReactNode, container?: NilContainer): NilContainer => {
+  const hostContainer: NilContainer = container ?? { head: null, children: [] };
+  let root = containerRoots.get(hostContainer);
+  if (root === undefined) {
+    root = nilReconciler.createContainer(hostContainer);
+    containerRoots.set(hostContainer, root);
+  }
+  nilReconciler.updateContainerSync(element, root);
+  return hostContainer;
+};
+
+export const unmountComponentAtNode = (container: NilContainer): void => {
+  const root = containerRoots.get(container);
+  if (root === undefined) return;
+  nilReconciler.updateContainerSync(null, root);
+  containerRoots.delete(container);
+};
+
+export const createPortal = (
+  children: React.ReactNode,
+  containerInfo: NilContainer,
+): React.ReactPortal => nilReconciler.createPortal(children, containerInfo);