migrate test helpers to typescript

test/helpers/actionCreators.js → test/helpers/actionCreators.ts

@@ -7,13 +7,14 @@ import {
   THROW_ERROR,
   UNKNOWN_ACTION
 } from './actionTypes'
+import { Action, AnyAction, Dispatch } from '../..'
 
-export function addTodo(text) {
+export function addTodo(text: string): AnyAction {
   return { type: ADD_TODO, text }
 }
 
-export function addTodoAsync(text) {
-  return dispatch =>
+export function addTodoAsync(text: string) {
+  return (dispatch: Dispatch): Promise<void> =>
     new Promise(resolve =>
       setImmediate(() => {
         dispatch(addTodo(text))
@@ -22,49 +23,49 @@ export function addTodoAsync(text) {
     )
 }
 
-export function addTodoIfEmpty(text) {
-  return (dispatch, getState) => {
+export function addTodoIfEmpty(text: string) {
+  return (dispatch: Dispatch, getState: () => any) => {
     if (!getState().length) {
       dispatch(addTodo(text))
     }
   }
 }
 
-export function dispatchInMiddle(boundDispatchFn) {
+export function dispatchInMiddle(boundDispatchFn: () => void): AnyAction {
   return {
     type: DISPATCH_IN_MIDDLE,
     boundDispatchFn
   }
 }
 
-export function getStateInMiddle(boundGetStateFn) {
+export function getStateInMiddle(boundGetStateFn: () => void): AnyAction {
   return {
     type: GET_STATE_IN_MIDDLE,
     boundGetStateFn
   }
 }
 
-export function subscribeInMiddle(boundSubscribeFn) {
+export function subscribeInMiddle(boundSubscribeFn: () => void): AnyAction {
   return {
     type: SUBSCRIBE_IN_MIDDLE,
     boundSubscribeFn
   }
 }
 
-export function unsubscribeInMiddle(boundUnsubscribeFn) {
+export function unsubscribeInMiddle(boundUnsubscribeFn: () => void): AnyAction {
   return {
     type: UNSUBSCRIBE_IN_MIDDLE,
     boundUnsubscribeFn
   }
 }
 
-export function throwError() {
+export function throwError(): Action {
   return {
     type: THROW_ERROR
   }
 }
 
-export function unknownAction() {
+export function unknownAction(): Action {
   return {
     type: UNKNOWN_ACTION
   }

test/helpers/middleware.ts

@@ -0,0 +1,12 @@
+import { MiddlewareAPI, Dispatch, AnyAction } from '../..'
+
+type ThunkAction<T extends any = any> = T extends AnyAction
+  ? AnyAction
+  : T extends Function
+  ? T
+  : never
+
+export function thunk({ dispatch, getState }: MiddlewareAPI) {
+  return (next: Dispatch) => <T>(action: ThunkAction) =>
+    typeof action === 'function' ? action(dispatch, getState) : next(action)
+}

test/helpers/reducers.js → test/helpers/reducers.ts

@@ -6,14 +6,21 @@ import {
   UNSUBSCRIBE_IN_MIDDLE,
   THROW_ERROR
 } from './actionTypes'
+import { AnyAction } from '../..'
 
-function id(state = []) {
+function id(state: { id: number }[] = []) {
   return (
     state.reduce((result, item) => (item.id > result ? item.id : result), 0) + 1
   )
 }
 
-export function todos(state = [], action) {
+export interface Todo {
+  id: number
+  text: string
+}
+export type TodoAction = { type: 'ADD_TODO'; text: string } | AnyAction
+
+export function todos(state: Todo[] = [], action: TodoAction) {
   switch (action.type) {
     case ADD_TODO:
       return [
@@ -28,7 +35,7 @@ export function todos(state = [], action) {
   }
 }
 
-export function todosReverse(state = [], action) {
+export function todosReverse(state: Todo[] = [], action: TodoAction) {
   switch (action.type) {
     case ADD_TODO:
       return [
@@ -43,7 +50,12 @@ export function todosReverse(state = [], action) {
   }
 }
 
-export function dispatchInTheMiddleOfReducer(state = [], action) {
+export function dispatchInTheMiddleOfReducer(
+  state = [],
+  action:
+    | { type: 'DISPATCH_IN_MIDDLE'; boundDispatchFn: () => void }
+    | AnyAction
+) {
   switch (action.type) {
     case DISPATCH_IN_MIDDLE:
       action.boundDispatchFn()
@@ -53,7 +65,12 @@ export function dispatchInTheMiddleOfReducer(state = [], action) {
   }
 }
 
-export function getStateInTheMiddleOfReducer(state = [], action) {
+export function getStateInTheMiddleOfReducer(
+  state = [],
+  action:
+    | { type: 'DISPATCH_IN_MIDDLE'; boundGetStateFn: () => void }
+    | AnyAction
+) {
   switch (action.type) {
     case GET_STATE_IN_MIDDLE:
       action.boundGetStateFn()
@@ -63,7 +80,12 @@ export function getStateInTheMiddleOfReducer(state = [], action) {
   }
 }
 
-export function subscribeInTheMiddleOfReducer(state = [], action) {
+export function subscribeInTheMiddleOfReducer(
+  state = [],
+  action:
+    | { type: 'DISPATCH_IN_MIDDLE'; boundSubscribeFn: () => void }
+    | AnyAction
+) {
   switch (action.type) {
     case SUBSCRIBE_IN_MIDDLE:
       action.boundSubscribeFn()
@@ -73,7 +95,12 @@ export function subscribeInTheMiddleOfReducer(state = [], action) {
   }
 }
 
-export function unsubscribeInTheMiddleOfReducer(state = [], action) {
+export function unsubscribeInTheMiddleOfReducer(
+  state = [],
+  action:
+    | { type: 'DISPATCH_IN_MIDDLE'; boundUnsubscribeFn: () => void }
+    | AnyAction
+) {
   switch (action.type) {
     case UNSUBSCRIBE_IN_MIDDLE:
       action.boundUnsubscribeFn()
@@ -83,7 +110,7 @@ export function unsubscribeInTheMiddleOfReducer(state = [], action) {
   }
 }
 
-export function errorThrowingReducer(state = [], action) {
+export function errorThrowingReducer(state = [], action: AnyAction) {
   switch (action.type) {
     case THROW_ERROR:
       throw new Error()