react-test-config

Configure the React testing environment for improved performance.

What it does

React 19 collects owner stacks (component stack traces) on every render. This is useful for debugging in development, but adds measurable overhead during tests. react-test-config disables this behaviour so your test suite runs faster.

Installation

npm install --save-dev react-test-config
# or
yarn add --dev react-test-config
# or
pnpm add --save-dev react-test-config

Peer dependency: React 19 (react@^19.0.0).

Usage

Call disableOwnerStacks() once, before your tests run. The right place is a setup file that your test runner loads before the test suite.

To disable owner-stack collection:

import { disableOwnerStacks } from 'react-test-config';

disableOwnerStacks();

Jest

Add the setup file to jest.config.js:

module.exports = {
  setupFiles: ['./jest.setup.ts'],
};

Vitest

Add the setup file to vitest.config.ts:

export default {
  test: {
    setupFiles: ['./vitest.setup.ts'],
  },
};

Recommended with

This package is particularly useful when testing React Native and React applications with:

• React Native Testing Library — testing utilities for React Native
• React Testing Library — testing utilities for React DOM
• Reassure — performance regression testing for React and React Native. Disabling owner stacks stabilises measurement results and resolves bimodal test result distributions caused by React's stack collection overhead

Configuration

RTC_SKIP_DISABLE_OWNER_STACKS

Set this environment variable to any truthy value to make disableOwnerStacks() a no-op. This is useful when you want to temporarily re-enable owner stacks — for example, to debug a component hierarchy without changing your setup file.

RTC_SKIP_DISABLE_OWNER_STACKS=1 npx jest

API

disableOwnerStacks()

Disables React's owner-stack collection by forcing React's internal recentlyCreatedOwnerStacks value to Infinity. Respects the RTC_SKIP_DISABLE_OWNER_STACKS environment variable.

License

MIT