Employee list doesn't load in Firefox

[sistemico]

No description provided.

[josx]

After some research the problem is on flatMap function on RXJS (getEmployeeById)
mergeMap is an alias for flatMap:

Here a clue to fix it:
ReactiveX/rxjs#3864

[josx]

Forget the above.

The real problem is that in the marshalling func we are using BigInt, which is currently not supported on Firefox.

BigInt is on stage 3 of the proposal flow. (https://github.com/tc39/proposal-bigint)

Here PR
#49