It allows you to easily dump things from a RxJS Observable

rxjs-debug.ts

import {tap} from 'rxjs/operators';

export function rxjsDebug<T>(context: string) {
  return tap<T>(
    v => {
      console.log(`next(${context})`, v);
    },
    e => {
      console.log(`error(${context})`, e);
    },
    () => {
      console.log(`complete(${context})`);
    }
  );
}

/* Example usage
const subject = new Subject();
const subscription = subject.pipe(rxjsDebug('subject')).subscribe();
const subject.next('Hi'); // will log `'next(subject)' 'Hi`
*/