Identify start and end date in a snapshot date column

Hi

1. Group by ID, sort by Date and add Index

2. LocalGroup  if DateMax-DateMin = IndexMax-IndexMin then same group, else new group

let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("dY7BCcAwEMN28TvQxHfpMkf2XyOhrxZR8EtI4CoNNfVxnbk7tFrJREH0hGZohmYYDINW0kpak9bkiS/KH+um9UJrAw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"User ID" = _t, #"Snapshot Date" = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"User ID", Int64.Type}, {"Snapshot Date", type date}}),
#"Group1-Sort+Index" = Table.Group(
   #"Changed Type",
   {"User ID"},
   {{"Data", each Table.AddIndexColumn(Table.Sort(_,{{"Snapshot Date", Order.Ascending}}), "Index"),
   type table [User ID=nullable number, Snapshot Date=nullable date, Index=Int64.Type]}}),
#"Group2-LocalGroup" = Table.AddColumn(
   #"Group1-Sort+Index",
   "Data2",
   each Table.Group(
      [Data],
      {"User ID", "Snapshot Date", "Index"},
      {{"Start", each List.Min([Snapshot Date]), type nullable date},
       {"End", each List.Max([Snapshot Date]), type nullable date}},
      GroupKind.Local,
      (x,y)=> if(y[Index]-x[Index])=Duration.Days(y[Snapshot Date]-x[Snapshot Date]) then 0 else 1
   )[[User ID],[Start],[End]]),
Data2 = Table.Combine(#"Group2-LocalGroup"[Data2])
in
Data2

Stéphane