How to debug flux variable and split _time to separate date and time strings?

Welcome & Getting Started
1

I’d wish to post my last measurement data to an external web service.

That web service requires a date in YYYYMMDD format and the time in HH:MM format.

How to retrieve these two items from the _time column of a query in flux?

And how to debug the output before http posting it? (An example how to stream a variable as data will help).

Would this flux code below do the job?

import "strings"
datetime = from(bucket: "dsm")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["equipment_id_electricity"] == "${ID_ELECTRICITY_6}")
  |> last()
  |> schema.fieldsAsCols()
  |> limit(n: 1)
  |> keep(columns: ["_time"])

d=strings.replaceAll(v: strings.substring(v: string(v: ${datetime}), start: 0, end: 10), t: "-", u: "")
t=strings.substring(v: string(v: ${datetime}), start: 11, end: 5)

Thanks in advance.