feat(redux): update to redux v4 (#501)

BREAKING CHANGE: redux-observable now requires redux v4. The new version of redux is mostly the same, however it required us to change the `createEpicMiddleware` API. See https://redux-observable.js.org/MIGRATION.html

package.json

@@ -64,7 +64,7 @@
  },
  "homepage": "https://github.com/redux-observable/redux-observable#README.md",
  "peerDependencies": {
    "redux": ">=3 <4",
    "redux": ">=4 <5",
    "rxjs": ">=6.0.0-beta.0 <7"
  },
  "devDependencies": {
@@ -95,7 +95,7 @@
    "gulp-babel": "^6.1.2",
    "json-server": "^0.10.0",
    "mocha": "^3.5.3",
    "redux": "^3.5.2",
    "redux": "^4.0.0",
    "rimraf": "^2.5.4",
    "rxjs": "^6.0.0",
    "sinon": "^4.5.0",

test/createEpicMiddleware-spec.js

@@ -7,6 +7,7 @@ import { createEpicMiddleware, combineEpics, ActionsObservable, StateObservable,
import { resetDeprecationsSeen } from '../lib/cjs/utils/console';
import { of, empty, merge } from 'rxjs';
import { mapTo, filter, map, mergeMap, startWith, ignoreElements, distinctUntilChanged } from 'rxjs/operators';
import { initAction } from './initAction';

describe('createEpicMiddleware', () => {
  let spySandbox;
@@ -103,9 +104,7 @@ describe('createEpicMiddleware', () => {
    store.dispatch({ type: 'PING' });

    expect(store.getState()).to.equal(2);
    expect(actions).to.deep.equal([{
      type: '@@redux/INIT'
    }, {
    expect(actions).to.deep.equal([initAction, {
      type: 'PING'
    }, {
      type: 'PONG',
@@ -167,9 +166,7 @@ describe('createEpicMiddleware', () => {
    store.dispatch({ type: 'FIRST' });

    expect(store.getState().value).to.equal(8);
    expect(actions).to.deep.equal([{
      type: '@@redux/INIT'
    }, {
    expect(actions).to.deep.equal([initAction, {
      type: 'FIRST'
    }, {
      type: 'STATE',
@@ -209,9 +206,7 @@ describe('createEpicMiddleware', () => {

    expect(console.warn.callCount).to.equal(1);
    expect(console.warn.getCall(0).args[0]).to.equal('redux-observable | WARNING: You accessed state$.value inside one of your Epics, before your reducers have run for the first time, so there is no state yet. You\'ll need to wait until after the first action (@@redux/INIT) is dispatched or by using state$ as an Observable.');
    expect(store.getState()).to.deep.equal([{
      type: '@@redux/INIT'
    }, {
    expect(store.getState()).to.deep.equal([initAction, {
      type: 'PONG',
      state: undefined
    }, {
@@ -268,7 +263,7 @@ describe('createEpicMiddleware', () => {
    store.dispatch({ type: 'FIRE_2' });

    expect(store.getState()).to.deep.equal([
      { type: '@@redux/INIT' },
      initAction,
      { type: 'FIRE_1' },
      { type: 'ACTION_1' },
      { type: 'FIRE_2' },
@@ -291,7 +286,7 @@ describe('createEpicMiddleware', () => {
    middleware.run(rootEpic);

    expect(store.getState()).to.deep.equal([
      { type: '@@redux/INIT' },
      initAction,
      { type: 'ACTION_1' },
      { type: 'ACTION_2' }
    ]);
@@ -321,7 +316,7 @@ describe('createEpicMiddleware', () => {
    middleware.run(rootEpic);

    expect(store.getState()).to.deep.equal([
      { type: '@@redux/INIT' },
      initAction,
      { type: 'ACTION_1' },
      { type: 'ACTION_2' },
      { type: 'ACTION_3' },
@@ -394,7 +389,7 @@ describe('createEpicMiddleware', () => {
    middleware.run(epic);

    expect(store.getState()).to.deep.equal([
      { type: '@@redux/INIT' },
      initAction,
      { type: 3 }
    ]);
  });

test/initAction.d.ts

@@ -0,0 +1 @@
export const initAction: { type: string };

test/initAction.js

@@ -0,0 +1,3 @@
import { __DO_NOT_USE__ActionTypes as actionTypes } from 'redux';

export const initAction = { type: actionTypes.INIT };

test/typings.ts

@@ -6,6 +6,7 @@ import { map, mapTo, mergeMap } from 'rxjs/operators';

import { createEpicMiddleware, Epic, combineEpics,
  EpicMiddleware, ActionsObservable, StateObservable, ofType } from '../';
import { initAction } from './initAction';

interface State {
  foo: string
@@ -170,27 +171,27 @@ store.dispatch({ type: 'EIGHTH', payload: 'eighth-payload' });
store.dispatch({ type: 'NINTH', payload: 'ninth-payload' });

expect(store.getState()).to.deep.equal([
  { "type": "@@redux/INIT" },
  initAction,
  { "type": "fourth" },
  { "type": "fourth" },
  { "type": "FIRST" },
  { "type": "first",
    "payload": [
      { "type": "@@redux/INIT" },
      initAction,
      { "type": "fourth" },
      { "type": "fourth" },
      { "type": "FIRST" }
    ]
  },
  { "type": "first",
    "payload": [
      { "type": "@@redux/INIT" },
      initAction,
      { "type": "fourth" },
      { "type": "fourth" },
      { "type": "FIRST" },
      { "type": "first",
        "payload": [
          { "type": "@@redux/INIT" },
          initAction,
          { "type": "fourth" },
          { "type": "fourth" },
          { "type": "FIRST" }