Function coreReady

coreReady(listenerId, fn): void
JMap.Event.Main.on.coreReady

This event is triggered once:
- the jmapserverjmapserver-ng-core library is loaded,
- the redux store and its reducers are also loaded,
- The initial session validation has been run. At thas point if the session has successfully been validated, the logged-in user will also be available
Parameters
- listenerId: string
  Your listener id (must be unique)
- fn: (() => void)
  Your listener function
  - - (): void
    - Returns void
Returns void
Example
```
// log a message in the console once the core library is loaded
JMap.Event.Main.on.coreReady(
  "custom-core-ready",
  () => {
    if (JMap.User.getToken() !== "-1") {
      console.log(`Logged in username is: "${JMap.User.getUsername()}"`)
    } else {
      console.log(`No user logged in`)
    }
  }
)
```