# TypeError: Cannot read properties of undefined (reading 'params')

- **ID:** `react/typeerror-cannot-read-properties-of-undefined-reading-params`
- **Domain:** react
- **Category:** type_error
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

Code attempts to access route parameters (e.g., `useParams()` or `match.params`) but the component is not rendered within a Route context, or the route path does not define the expected parameter.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| React Router 6.20.0 | active | — | — |
| React Router 5.3.4 | active | — | — |
| React 18.2.0 | active | — | — |

## Workarounds

1. **Ensure the component is wrapped in a Route: `<Route path="/user/:id" element={<UserComponent />} />` and access params via `useParams()` hook inside UserComponent.** (90% success)
   ```
   Ensure the component is wrapped in a Route: `<Route path="/user/:id" element={<UserComponent />} />` and access params via `useParams()` hook inside UserComponent.
   ```
2. **If using class component, use `withRouter` HOC (React Router v5) or wrap with `useParams` in a function component and pass as props.** (85% success)
   ```
   If using class component, use `withRouter` HOC (React Router v5) or wrap with `useParams` in a function component and pass as props.
   ```
3. **Check that the route path includes the parameter (e.g., `/user/:id`) and the URL actually matches.** (80% success)
   ```
   Check that the route path includes the parameter (e.g., `/user/:id`) and the URL actually matches.
   ```

## Dead Ends

- **** — The underlying issue (component outside Router) remains, leading to other bugs. (90% fail)
- **** — Both exports exist, but the context provider difference is the real issue. (85% fail)