what the author wants doesn't exists because the two saves will not actually run in parallel in any case.
Not with `async save(); async save();`
nor with `Promise.all`
nor with any callback or any other means.
the author is conflating parallel with concurrent programming.
and in (the mono-thread world of) javascript the two calls will still occurs sequentially.
Consider that 'save()' might do multiple steps under the covers (network, database, localstorage, whatever). Allowing those steps to run interleaved, if necessary (with Promise.all), might be quite different from serializing the 'save()' calls completely in the caller.
So while it is true that neither is truly parallel in the "parallel vs concurrent" sense, it is not true that the "sequential"/"concurrent" execution of both styles has the same performance characteristics.
the author is conflating parallel with concurrent programming.
and in (the mono-thread world of) javascript the two calls will still occurs sequentially.