Spew some JSON to a named file

spewjson.go

func spewJSON(fn, data string) { 
  w, err := os.Create(fn)
  if err != nil { 
    panic(err)
  } 
  defer w.Close()

  var v any
  json.Unmarshal([]byte(data), &v)
  e := json.NewEncoder(w)
  e.SetIndent("", "  ")
  e.Encode(v)
}