interval in Observables

Observable.interval(1000).takeWhile(() => true).subscribe(a => {

console.log('called');

}

);

Angular 6 CLI command

ng generate class [name] generates a class
ng generate component [name] generates a component
ng generate directive [name] generates a directive
ng generate enum [name] generates an enumeration
ng generate guard [name] generates a guard
ng generate interface [name] <type> generates an interface
ng generate module [name] generates an NgModule
ng generate pipe [name] generates a pipe
ng generate service [name] generates a service

ng build
ng test
ng doc