Grafana: Evaluate date name (Flux)

Goal: Add two columns (namedMonth and namedDay) with name of the month and day.
Steps:

• Aggregate the data with an window of 1d and the function last.
• Group the data by _time.
• Calculate the sum for each timeseries (foreach grouped _time).
• Truncate the data to whole days.
• Select first to remove the last not completed day.
• Evaluate the month and the day and add these as new columns.
• Add pivot function to make the format working with Grafana.

import "date" //import library to add date functions
timewindow = 1d //timewindow size

from(bucket: <YOUR_BUCKET>)
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => 
    r._measurement == "<YOUR_MEASUREMENT>"
  )
  |> aggregateWindow(every: timewindow, fn: last, createEmpty: false)
  |> group(columns: ["_time"])
  |> sum()
  |> truncateTimeColumn(unit: timewindow) //truncate to whole days
  |> first() //remove the calculated to now()
  |> map(fn: (r) => ({ r with //Valuemapping of monthnumber to monthname
    namedMonth:
      if (date.month(t: r._time)) == 1 then "January" 
      else if (date.month(t: r._time)) == 2 then "February"
      else if (date.month(t: r._time)) == 3 then "March"
      else if (date.month(t: r._time)) == 4 then "April"
      else if (date.month(t: r._time)) == 5 then "May"
      else if (date.month(t: r._time)) == 6 then "June"
      else if (date.month(t: r._time)) == 7 then "July"
      else if (date.month(t: r._time)) == 8 then "August"
      else if (date.month(t: r._time)) == 9 then "September"
      else if (date.month(t: r._time)) == 10 then "October"
      else if (date.month(t: r._time)) == 11 then "November"
      else if (date.month(t: r._time)) == 12 then "December"
      else "error",
    namedDay:
      if (date.weekDay(t: r._time)) == 0 then "Sunday" 
      else if (date.weekDay(t: r._time)) == 1 then "Monday"
      else if (date.weekDay(t: r._time)) == 2 then "Tuesday"
      else if (date.weekDay(t: r._time)) == 3 then "Wednesday"
      else if (date.weekDay(t: r._time)) == 4 then "Thursday"
      else if (date.weekDay(t: r._time)) == 5 then "Friday"
      else if (date.weekDay(t: r._time)) == 6 then "Saturday"
      else "error"
  }))
  |> pivot(rowKey: ["_time"], columnKey: ["namedMonth", "namedDay"], valueColumn: "_value") //formating for Grafana