how do I use the getContext effect in a Redux Saga

1. Create a Context Object: Create a context object that contains the values you want to inject into your sagas. This can be a singleton API service or any other shared value across your application.

2. Pass the Context Object to the Saga Middleware: When creating the saga middleware, pass the context object as an option. This sets the context for all sagas that are run using this middleware.

3. Use `getContext` Effect in Your Saga: In your saga, use the `getContext` effect to retrieve the context values. This allows you to access the shared values without having to import them statically.

Here is an example of how you can use `getContext` in a saga:

javascript
import { call, getContext } from "redux-saga/effects";

// No more API import:

// import api from './api'

export function* fetchInventorySaga() {

// Get the api value out of the shared context:

const api = yield getContext("api");

const inventory = yield call(api.getInventory);

// Do something with the inventory data...

By using `getContext`, you can decouple your sagas from statically-declared singletons and make your code more modular and testable.

Here is a more detailed example of how you can set up context in your main application and use it in your sagas:

javascript
import createSagaMiddleware from "redux-saga";
import api from "./api";

const sagaMiddleware = createSagaMiddleware({
  context: {
    api, // our singleton API value
  },
});

const store = createStore(reducer, applyMiddleware(sagaMiddleware));

In this example, the `api` singleton is set as the context for all sagas that are run using this middleware. Then, in your sagas, you can use `getContext` to access the `api` value:

javascript
import { call, getContext } from "redux-saga/effects";

export function* fetchInventorySaga() {
  const api = yield getContext("api");
  const inventory = yield call(api.getInventory);
  // Do something with the inventory data....
}

By using `getContext`, you can manage shared values across your application in a more organized and testable way.