Vitest Browser React V4: Radix DropdownMenu Error

Are you encountering an element reference error when testing Radix DropdownMenu with modal={true} in Vitest Browser React v4? You're not alone! This article dives deep into a peculiar bug reported by a developer using Playwright as their provider. We'll explore the issue, the steps to reproduce it, and potential workarounds.

Understanding the Bug: A Deep Dive

The core of the problem lies in how Vitest Browser React handles element referencing when a Radix DropdownMenu is rendered with the modal={true} property. Let's break down the scenario:

1. The Setup: The developer is using Playwright within a Vitest v4 environment to test a React application that utilizes Radix UI's DropdownMenu component.
2. The Trigger: They use user event to click the DropdownMenuTrigger, which successfully opens the DropdownMenu.
3. The Initial Success: While the DropdownMenu is open, they can reference elements within the menu without any issues. This indicates that Vitest Browser React is correctly interacting with the newly rendered elements.
4. The Error: The trouble arises when they attempt to reference elements that were declared before the DropdownMenu was opened. This results in a VitestBrowserElementError: Cannot find element with locator error.
5. The Modal Mystery: Interestingly, this error only occurs when the DropdownMenu is configured with modal={true}. Setting modal={false} resolves the issue, allowing the developer to reference elements both inside and outside the menu.

This behavior suggests that the modal property might be influencing how Vitest Browser React handles the element tree or the context in which elements are searched. When modal={true}, the DropdownMenu likely creates a modal overlay, which could be isolating the menu's content in a way that interferes with element referencing outside of it.

The developer noted that while setting modal={false} works as a temporary fix for their current test, it might not be a viable long-term solution, especially when the modal behavior is a critical part of the component's functionality. This highlights the importance of understanding and resolving this bug.

Reproducing the Issue: A Step-by-Step Guide

To better understand and address this bug, it's crucial to have a clear and reproducible test case. The developer has generously provided a Minimal Reproducible Example (MRE) on GitHub. This MRE is a fresh React Router repository with a fresh Vitest v4 setup, making it easy for others to replicate the issue. Here’s a breakdown of how you can reproduce the bug:

1. Clone the Repository: Start by cloning the MRE repository from GitHub: git clone https://github.com/onyedikachi23/dropdown-modal-vitest-browser-issue
2. Install Dependencies: Navigate into the cloned directory and install the necessary dependencies using your preferred package manager (pnpm in this case): pnpm install
3. Run the Tests: Execute the Vitest tests using the command: pnpm test
4. Observe the Error: You should encounter the VitestBrowserElementError when the test attempts to reference elements outside the DropdownMenu while modal={true}.

By following these steps, you can verify the bug and begin to investigate the root cause. The MRE provides a controlled environment, eliminating external factors and making it easier to pinpoint the problem.

System Information: The Context of the Bug

Understanding the environment in which the bug occurs is vital for troubleshooting. The developer has provided detailed system information, which can help identify potential compatibility issues or environment-specific behaviors. Here's a summary of the key system details:

• Operating System: Linux 6.11 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
• CPU: (4) x64 Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
• Memory: 1.83 GB / 7.64 GB
• Container: Yes (This indicates the tests might be running in a containerized environment, which could introduce additional considerations.)
• Shell: 5.2.21 - /bin/bash
• Node.js Version: 23.9.0
• npm Version: 11.2.0
• pnpm Version: 10.8.1
• Watchman Version: 4.9.0
• Browsers: The developer has tested with Brave Browser, Chrome, Firefox, and Firefox Developer Edition.
• npm Packages:
  • @vitejs/plugin-react: ^5.1.0 => 5.1.0
  • @vitest/browser-playwright: ^4.0.3 => 4.0.3
  • vite: ^7.1.7 => 7.1.12
  • vitest: ^4.0.3 => 4.0.3
  • vitest-browser-react: ^2.0.0 => 2.0.0

This information helps to narrow down the potential causes of the bug. For example, knowing the specific versions of Vitest, Vitest Browser React, and Playwright can help determine if the issue is related to a recent update or a specific version combination.

Potential Causes and Workarounds

Based on the information provided, here are some potential causes and workarounds for this bug:

Potential Causes:

1. Modal Isolation: As mentioned earlier, the modal={true} property likely creates a modal overlay, which might be isolating the DropdownMenu's content in a separate context. This could prevent Vitest Browser React from correctly querying elements outside the modal.
2. Playwright Context: Playwright's context management might be interacting unexpectedly with the modal. Each modal might be creating a new context, and the element query might not be searching across contexts.
3. Vitest Browser React's Element Querying: There might be a bug in how Vitest Browser React queries elements when modals are involved. The library might not be correctly handling the DOM structure created by the modal.
4. Timing Issues: It's possible that the elements outside the modal are not fully rendered or accessible when the query is executed. This could be due to asynchronous rendering or other timing-related factors.

Workarounds:

1. Set modal={false} (Temporary): As the developer noted, setting modal={false} resolves the issue. However, this is not a long-term solution if the modal behavior is essential.
2. Query within the Modal: If possible, try to limit your queries to elements within the DropdownMenu while it's open. This might avoid the issue of referencing elements outside the modal's context.
3. Explicitly Wait for Elements: Before querying elements outside the modal, try using Playwright's waitForSelector or similar methods to ensure that the elements are fully rendered and accessible.
4. Use Different Locators: Experiment with different locator strategies (e.g., using getByText, getByRole, or data-testid attributes) to see if a specific locator type works better in this scenario.
5. Debounce or Delay Queries: Introduce a small delay before querying elements outside the modal. This might give the DOM time to update and make the elements accessible.

Community Validation and Next Steps

The developer has taken the crucial step of validating their findings against the Code of Conduct, Contributing Guidelines, and documentation. They've also confirmed that the issue isn't a duplicate and have provided a minimal reproducible example. This thoroughness is commendable and significantly aids in resolving the bug.

The next steps involve:

1. Further Investigation: The Vitest team and community members should investigate the MRE to pinpoint the exact cause of the bug.
2. Code Analysis: A deep dive into Vitest Browser React's code, particularly the element querying logic and modal handling, is necessary.
3. Testing and Debugging: Implement targeted tests to isolate the issue and debug the code.
4. Solution Implementation: Once the root cause is identified, develop a fix that addresses the bug without introducing regressions.
5. Community Feedback: Share the solution with the community and gather feedback to ensure it effectively resolves the issue.

Conclusion

The element reference error encountered when testing Radix DropdownMenu with modal={true} in Vitest Browser React v4 is a complex issue that requires careful investigation. The detailed report and MRE provided by the developer are invaluable resources for the Vitest team and community. By understanding the bug, reproducing it, and exploring potential causes and workarounds, we can collectively work towards a solution that ensures seamless testing of modal components in React applications.

If you're experiencing this issue or have insights to share, please contribute to the discussion on the Vitest GitHub repository. Your input can help accelerate the resolution process and benefit the entire community.

For further information on Vitest and its capabilities, consider exploring the official Vitest documentation and related resources. You can also find helpful information on testing React components with Vitest in articles like this one on Testing Library. This will provide you with a broader understanding of testing best practices and techniques that can be applied to your projects.