Angular / Typescript中的导出*（星号）是什么意思

Question

I was going through a component communication example in Angular then I saw this:

export * from './message.service';

What is the role of this export action and why is it done in another file that is not message.service? (Yet in the message.service.ts there is an export function which exports the service class)

export class MessageService {...

Answer 1

This re-export all the content from the './message.service' . This is usally done do package multiple modules into a single container module that can more easily be imported by clients. This feature is also called Module Redirects in the documentation.

Read here or the docs here

Answer 2

For example, you can create index.ts which will reexport all things from a certain directory which have a lot of files which every one of them exports something. Then you can simply import from that one file.