log-diff.ts

import { Observable } from "rxjs";
import { valueOf } from 'microstates'
import { diff } from 'deep-object-diff'

export const logDiff = (name: string) => <T>(source: Observable<T>) =>
new Observable<T>(observer => {
  let last: any;
  return source.subscribe({
    next(x) {
      console.log(name, diff(valueOf(last), valueOf(x)));
      last = x;
      observer.next(x);
    },
    error(err) { observer.error(err); },
    complete() { observer.complete(); }
  })
})

log-stack-trace.ts

import { Observable } from "rxjs";
import * as captureStackTrace from 'capture-stack-trace';
import { get } from 'stack-trace';

// @ts-ignore
if (!Error.captureStackTrace) {
  // @ts-ignore
  Error.captureStackTrace = captureStackTrace;
}

export const logStackTrace = (name: string, belowFn?: () => void) => console.log(name, get(belowFn))

export const logStackTraceOp = (belowFn?: () => void) => <T>(source: Observable<T>) =>
new Observable<T>(observer => {
  return source.subscribe({
    next(x) {
      logStackTrace('STACK TRACE', belowFn);
      observer.next(x);
    },
    error(err) { observer.error(err); },
    complete() { observer.complete(); }
  })
})