React redux how to use getState()

Question

I am fetching data from the Firebase Real-time database and storing it into my redux state. How can I create an action that will get the latest and most up to date state after the initial call?

const getIds = (state) => state.notes.activeNotes;

export const getUserNotes = (currentUserId) => (dispatch, getState) => {
  getFromFirebase(`/Notes/${currentUserId}/`, (response) => {
    var ids = Object.keys(response)
      dispatch(setNoteIds(ids)); //should dispatch ids something like this [1,2,3,4,5]
  })

  const test= getIds(getState());
  console.log(test); //current output []
}

Expected output: [1,2,3,4,5]
Actual output: []

Answer 1

Assuming the function getFromFirebase returns a promise then you can switch your method to async as following:

export const getUserNotes = (currentUserId) => async (dispatch, getState) => {
  // wait the result dispatched
  await getFromFirebase(`/Notes/${currentUserId}/`, (response) => {
    var ids = Object.keys(response)
      dispatch(setNoteIds(ids)); //should dispatch ids something like this [1,2,3,4,5]
  })
  
  const test= getIds(getState());
}

Or if the getFromFirebase is not a promise, you can wrap it up by a promise:

export const getUserNotes = (currentUserId) => async (dispatch, getState) => {
  // wrap in a promise
  await new Promise(resolve => {
    getFromFirebase(`/Notes/${currentUserId}/`, (response) => {
      var ids = Object.keys(response)
        dispatch(setNoteIds(ids)); //should dispatch ids something like this [1,2,3,4,5]
        resolve();
    })
  })
  
  const test= getIds(getState())
}