Visual Studio 2019 的 React Redux 项目模板，JavaScript 问题

Question

Can someone explain a piece of code (JavaScript + TypeScript) from React Redux Visual Studio template? The class I am requesting clarification is available here:

https://github.com/dotnet/aspnetcore/blob/master/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/ClientApp/src/store/WeatherForecasts.ts

Specific line of code that I wanted explanation is: requestWeatherForecasts: (startDateIndex: number): AppThunkAction<KnownAction> => (dispatch, getState)

I know, it is a simple syntax question, please help :)

Answer 1

So, first of all it's fully TypeScript :) It isn't a mixed code of JS and TS.

The requestWeatherForecasts function is a field of the actionCreators object and it receives the startDateIndex parameter which typed as a number. The function returns a new function or a thunk action https://github.com/reduxjs/redux-thunk which typed as AppThunkAction. AppThunkAction is an internal interface, you can find it in "store/index.js". KnownAction is an interface of possible arguments and it is passed as an argument for the AppThunkAction type.

Hope it will help you.

Answer 2

It's referring to an action creators. Have a look at redux-thunk middleware

https://github.com/reduxjs/redux-thunk