Q:

How to import ErrorObservable or _throw in rxjs6?  throw in rxjs

I am migrating to rxjs 6.0.0-ucandoit-rc.6.  In version 5.5.2 I was using ErrorObservable to create errorous observable. 
I was using the way recommended here: https://github.com/ReactiveX/rxjs/blob/master/doc/pipeable-operators.md

Because throw is a key word you could use _throw after import { _throw } from 'rxjs/observable/throw'. 

However this is not recommended way to import in rxjs6 anymore. 
What is correct way how to import _throw or ErrorObservable? 

A:

In RxJS version 6, _throw has been renamed to throwError and should be imported like this:
import { throwError } from "rxjs";

Alternatively, you can install rxjs-compat alongside rxjs version 6 to continue to use the old, version 5 exports:
import { _throw } from "rxjs/observable/throw";

For more information, see the migration guide.