takeUntilExampleEpic.js

import { from, of, concat } from 'rxjs';
import { catchError, mergeMap, switchMap, takeUntil } from 'rxjs/operators';
import { startSubmit, stopSubmit } from 'redux-form';

const exampleEpic = action$ =>
    action$.pipe(
      ofType(types.ACTION_REQUEST),
      switchMap(({ payload, meta }) => // yes, meta!
        concat(
          of(startSubmit(meta.formName)), // Here we define that this specific form is submitting 
          from(api.get(payload.data)).pipe(
            mergeMap(response =>
              of(
                addDataAction(response), // action 1
                pushInfoSnackbar('created successfully'), // action 2
                stopSubmit(meta.formName) // action 3
              )
            ),
            takeUntil(action$.ofType(types.PAGE_CHANGED)),
            catchError(() =>
              of(pushWarningSnackbar('Failed to create shareable folder'), stopSubmit(meta.formName)); // failed action
            )
          )
        )
      )
    );