Added optional cancel action to the createAsyncAction API

[piotrwitek]

Description

Added optional cancel action to the createAsyncAction API

// actions.ts
import { createAsyncAction } from 'typesafe-actions';

const fetchTodosAsync = createAsyncAction(
  'FETCH_TODOS_REQUEST',
  'FETCH_TODOS_SUCCESS',
  'FETCH_TODOS_FAILURE',
  'FETCH_TODOS_CANCEL'
)<string, Todo[], Error, string>();

// epics.ts
import { fetchTodosAsync } from './actions';

const fetchTodosFlow: Epic<RootAction, RootAction, RootState, Services> = (action$, store, { todosApi }) =>
  action$.pipe(
    filter(isActionOf(fetchTodosAsync.request)),
    switchMap(action =>
      from(todosApi.getAll(action.payload)).pipe(
        map(fetchTodosAsync.success),
        catchError(pipe(fetchTodosAsync.failure, of)),
        takeUntil(action$.pipe(filter(isActionOf(fetchTodosAsync.cancel)))),
      )
    );

Related issues:

• Resolved Extend createAsyncAction to support cancellation #144

Checklist

• I have read CONTRIBUTING.md
• I have linked all related issues above
• I have rebased my branch

For bugfixes:

• I have added at least one unit test to confirm the bug have been fixed

For new features:

• I have updated API docs and tutorial (if applicable)
• I have added short examples to demonstrate new feature usage
• I have added type unit tests with dts-jest
• I have added runtime unit tests with dts-jest