# Error: The context value for 'MyContext' is undefined. Did you forget to wrap your component in a Provider with a value?

- **ID:** `react/context-value-undefined-reducer`
- **Domain:** react
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

A component tries to consume a context value that is undefined because the corresponding Provider is missing or does not provide a value prop.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| React 18.2.0 | active | — | — |
| React 19.0.0-beta.1 | active | — | — |

## Workarounds

1. **Ensure the component is wrapped in the correct Provider with a value prop. Example: <MyContext.Provider value={someValue}><ChildComponent /></MyContext.Provider>** (95% success)
   ```
   Ensure the component is wrapped in the correct Provider with a value prop. Example: <MyContext.Provider value={someValue}><ChildComponent /></MyContext.Provider>
   ```
2. **Check the context creation file to ensure the context is exported and imported correctly. Use named exports to avoid confusion.** (85% success)
   ```
   Check the context creation file to ensure the context is exported and imported correctly. Use named exports to avoid confusion.
   ```
3. **If using useReducer, pass the dispatch as part of the context value: const [state, dispatch] = useReducer(reducer, initialState); <MyContext.Provider value={{ state, dispatch }}>...</MyContext.Provider>** (90% success)
   ```
   If using useReducer, pass the dispatch as part of the context value: const [state, dispatch] = useReducer(reducer, initialState); <MyContext.Provider value={{ state, dispatch }}>...</MyContext.Provider>
   ```

## Dead Ends

- **** — The default value is used only if there is no Provider; if a Provider exists without a value, it still passes undefined. (70% fail)
- **** — This causes a mismatch between the context used in the Provider and the consumer. (80% fail)
- **** — Without a value prop, the Provider passes undefined, which is still undefined. (90% fail)