middleware receive immutable versions of state and actions

x-pack/plugins/endpoint/public/applications/endpoint/store/action.ts

@@ -10,6 +10,9 @@ import { RoutingAction } from './routing';
 import { PolicyListAction } from './policy_list';
 import { PolicyDetailsAction } from './policy_details';
 
+/**
+ * The entire set of redux actions recognized by our reducer.
+ */
 export type AppAction =
   | HostAction
   | AlertAction

x-pack/plugins/endpoint/public/applications/endpoint/store/alerts/middleware.ts

@@ -6,7 +6,6 @@
 
 import { IIndexPattern } from 'src/plugins/data/public';
 import { AlertResultList, AlertDetails } from '../../../../../common/types';
-import { AppAction } from '../action';
 import { MiddlewareFactory, AlertListState } from '../../types';
 import { isOnAlertPage, apiQueryParams, hasSelectedAlert, uiQueryParams } from './selectors';
 import { cloneHttpFetchQuery } from '../../../../common/clone_http_fetch_query';
@@ -29,7 +28,7 @@ export const alertMiddlewareFactory: MiddlewareFactory<AlertListState> = (coreSt
     return [indexPattern];
   }
 
-  return api => next => async (action: AppAction) => {
+  return api => next => async action => {
     next(action);
     const state = api.getState();
     if (action.type === 'userChangedUrl' && isOnAlertPage(state)) {

x-pack/plugins/endpoint/public/applications/endpoint/store/hosts/middleware.ts

@@ -7,10 +7,9 @@
 import { MiddlewareFactory } from '../../types';
 import { pageIndex, pageSize, isOnHostPage, hasSelectedHost, uiQueryParams } from './selectors';
 import { HostListState } from '../../types';
-import { AppAction } from '../action';
 
 export const hostMiddlewareFactory: MiddlewareFactory<HostListState> = coreStart => {
-  return ({ getState, dispatch }) => next => async (action: AppAction) => {
+  return ({ getState, dispatch }) => next => async action => {
     next(action);
     const state = getState();
     if (

x-pack/plugins/endpoint/public/applications/endpoint/store/index.ts

@@ -22,6 +22,7 @@ import { policyDetailsMiddlewareFactory } from './policy_details';
 import { GlobalState, MiddlewareFactory } from '../types';
 import { AppAction } from './action';
 import { EndpointPluginStartDependencies } from '../../../plugin';
+import { Immutable } from '../../../../common/types';
 
 const composeWithReduxDevTools = (window as any).__REDUX_DEVTOOLS_EXTENSION_COMPOSE__
   ? (window as any).__REDUX_DEVTOOLS_EXTENSION_COMPOSE__({ name: 'EndpointApp' })
@@ -37,10 +38,10 @@ export type Selector<S, R> = (state: S) => R;
  */
 export const substateMiddlewareFactory = <Substate>(
   selector: Selector<GlobalState, Substate>,
-  middleware: Middleware<{}, Substate, Dispatch<AppAction>>
-): Middleware<{}, GlobalState, Dispatch<AppAction>> => {
+  middleware: Middleware<{}, Substate, Dispatch<Immutable<AppAction> | AppAction>>
+): Middleware<{}, GlobalState, Dispatch<AppAction | Immutable<AppAction>>> => {
   return api => {
-    const substateAPI: MiddlewareAPI<Dispatch<AppAction>, Substate> = {
+    const substateAPI: MiddlewareAPI<Dispatch<AppAction | Immutable<AppAction>>, Substate> = {
       ...api,
       getState() {
         return selector(api.getState());

x-pack/plugins/endpoint/public/applications/endpoint/store/policy_details/selectors.ts

@@ -23,8 +23,8 @@ export const isOnPolicyDetailsPage = (state: Immutable<PolicyDetailsState>) => {
 };
 
 /** Returns the policyId from the url */
-export const policyIdFromParams: (state: PolicyDetailsState) => string = createSelector(
-  (state: PolicyDetailsState) => state.location,
+export const policyIdFromParams: (state: Immutable<PolicyDetailsState>) => string = createSelector(
+  state => state.location,
   (location: PolicyDetailsState['location']) => {
     if (location) {
       return location.pathname.split('/')[2];

x-pack/plugins/endpoint/public/applications/endpoint/types.ts

@@ -28,12 +28,19 @@ import {
 } from '../../../../ingest_manager/common';
 
 export { AppAction };
+
+/**
+ * Takes application-standard middleware dependencies
+ * and returns a redux middleware.
+ */
 export type MiddlewareFactory<S = GlobalState> = (
   coreStart: CoreStart,
   depsStart: EndpointPluginStartDependencies
 ) => (
-  api: MiddlewareAPI<Dispatch<AppAction>, S>
-) => (next: Dispatch<AppAction>) => (action: AppAction) => unknown;
+  api: MiddlewareAPI<Dispatch<Immutable<AppAction> | AppAction>, Immutable<S>>
+) => (
+  next: Dispatch<Immutable<AppAction> | AppAction>
+) => (action: Immutable<AppAction>) => unknown;
 
 export interface HostListState {
   hosts: HostMetadata[];