refactor: remove createNodeMock option (#45)

Author: mdjastrzebski

README.md

@@ -97,7 +97,6 @@ Configuration options for the test renderer. Many of these options correspond to
 | ------------------------------ | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
 | `textComponentTypes`           | `string[]`                                                                                       | Types of host components that are allowed to contain text nodes. Trying to render text outside of these components will throw an error. Useful for simulating React Native's text rendering rules.                                                                                               |
 | `publicTextComponentTypes`     | `string[]`                                                                                       | Host component types to display to users in error messages when they try to render text outside of `textComponentTypes`. Defaults to `textComponentTypes` if not provided.                                                                                                                       |
-| `createNodeMock`               | `(element: ReactElement) => object`                                                              | Function to create mock objects for refs. Called once per element that has a ref. Defaults to returning an empty object.                                                                                                                                                                         |
 | `transformHiddenInstanceProps` | `({ props, type }: { props: Record<string, unknown>; type: string }) => Record<string, unknown>` | Transforms host instance props when React marks an instance as hidden (for example, while Suspense fallback is shown). Return a new props object instead of mutating the provided one. When provided, hidden instances stay visible in `children` and `toJSON()` output using transformed props. |
 | `identifierPrefix`             | `string`                                                                                         | A string prefix React uses for IDs generated by `useId()`. Useful to avoid conflicts when using multiple roots.                                                                                                                                                                                  |
 | `isStrictMode`                 | `boolean`                                                                                        | Enable React Strict Mode. When enabled, components render twice and effects run twice in development.                                                                                                                                                                                            |

src/__tests__/create-node-mock.test.tsx

@@ -1,8 +1,9 @@
 import { beforeEach, describe, expect, test } from "@jest/globals";
-import { createElement } from "react";
+import { createElement, createRef, type Ref } from "react";
 
 import { createRoot } from "../renderer";
-import { renderWithAct } from "../test-utils/render";
+import type { TestInstance } from "../test-instance";
+import { getRootInstance, renderWithAct } from "../test-utils/render";
 
 beforeEach(() => {
   global.IS_REACT_ACT_ENVIRONMENT = true;
@@ -20,6 +21,14 @@ test("basic renderer usage", async () => {
   `);
 });
 
+test("refs receive TestInstance by default", async () => {
+  const renderer = createRoot();
+  const ref = createRef<TestInstance | null>();
+  await renderWithAct(renderer, <div ref={ref as Ref<HTMLDivElement>}>Hello</div>);
+  const rootInstance = getRootInstance(renderer);
+  expect(ref.current).toBe(rootInstance);
+});
+
 describe("textComponentTypes", () => {
   test("single allowed text component", async () => {
     const renderer = createRoot({

src/__tests__/renderer.test.tsx

@@ -1,10 +1,10 @@
-import type { ReactElement } from "react";
 import type { Fiber } from "react-reconciler";
 import ReactReconciler from "react-reconciler";
 import { DefaultEventPriority, NoEventPriority } from "react-reconciler/constants";
 
 import { Tag } from "./constants";
 import { mark, measureEnd, measureStart } from "./performance";
+import { TestInstance } from "./test-instance";
 import { formatComponentList } from "./utils";
 
 export type Type = string;
@@ -14,7 +14,6 @@ export type TransformHiddenInstanceProps = (input: { props: Props; type: Type })
 type ReconcilerConfig = {
   textComponentTypes?: string[];
   publicTextComponentTypes?: string[];
-  createNodeMock: (element: ReactElement) => object;
   transformHiddenInstanceProps?: TransformHiddenInstanceProps;
 };
 
@@ -48,7 +47,7 @@ export type TextInstance = {
 
 export type SuspenseInstance = object;
 export type HydratableInstance = object;
-export type PublicInstance = object | TextInstance;
+export type PublicInstance = object | null;
 export type UpdatePayload = unknown;
 export type ChildSet = unknown;
 export type TimeoutHandle = unknown;
@@ -351,20 +350,13 @@ const hostConfig: ReactReconciler.HostConfig<
 
     switch (instance.tag) {
       case Tag.Instance: {
-        const createNodeMock = instance.rootContainer.config.createNodeMock;
-        const mockNode = createNodeMock({
-          type: instance.type,
-          props: instance.props,
-          key: null,
-        });
-
-        nodeToInstanceMap.set(mockNode, instance);
-
-        return mockNode;
+        const testInstance = TestInstance.fromInstance(instance);
+        nodeToInstanceMap.set(testInstance, instance);
+        return testInstance;
       }
 
       default:
-        return instance;
+        return null;
     }
   },
 

src/reconciler.ts

@@ -12,8 +12,6 @@ import { TestInstance } from "./test-instance";
 // https://github.com/facebook/react/blob/main/packages/react-noop-renderer/src/createReactNoop.js
 // https://github.com/facebook/react/blob/main/packages/react-native-renderer/src/ReactFiberConfigFabric.js
 
-const defaultCreateMockNode = () => ({});
-
 const defaultOnUncaughtError = (error: unknown, errorInfo: ErrorInfo) => {
   console.error("Uncaught error:", error, errorInfo);
 };
@@ -37,9 +35,6 @@ export type RootOptions = {
    */
   publicTextComponentTypes?: string[];
 
-  /** Function to create mock nodes for refs. */
-  createNodeMock?: (element: ReactElement) => object;
-
   /**
    * Transform props when React marks a host instance as hidden (e.g. during Suspense fallback).
    * Receives `{ props, type }` and should return a new props object.
@@ -100,7 +95,6 @@ export function createRoot(options?: RootOptions): Root {
     config: {
       textComponentTypes: options?.textComponentTypes,
       publicTextComponentTypes: options?.publicTextComponentTypes,
-      createNodeMock: options?.createNodeMock ?? defaultCreateMockNode,
       transformHiddenInstanceProps: options?.transformHiddenInstanceProps,
     },
   };