Problem with select in redux-saga. Error: call: argument of type {context, fn} has undefined or null `fn`

The error is not with your selector but with your yield call - it takes the function as an arg followed by the arguments to pass to the function: https://redux-saga.js.org/docs/api/#callfn-args. So it should be:

const response = yield call(getTweets, buttonStatus);

Otherwise looks good!