Cannot find module 'rxjs/subject/BehaviorSubject'
import {BehaviorSubject} from 'rxjs/BehaviorSubject';
rxjs 6.x
import {BehaviorSubject} from 'rxjs';
See also
import {BehaviorSubject} from 'rxjs/BehaviorSubject';
rxjs 6.x
import {BehaviorSubject} from 'rxjs';
See also