Pondjs fixedWindowRollup example needed

Could someone show me how to use the pondjs timeSeries.fixedWindowRollup because I can’t figure out what I’m doing wrong.

I’d like to resample a dataset to have uniform timestamps, so here is the code I’m using based on doc and what I see in the source:

const data = res.map((data: any) => {
    return {
      timestamp: new Date(data.End).getTime(),
      value: data.Value,
    }
  })

  const ts = timeSeries({
    points: data.map((entry: any) => [entry.timestamp, entry.value]),
    columns: ["time", "value"],
    name: "data",
  })
  .fixedWindowRollup({
    window: window(duration("1day")),
    //aggregation: { value: { value: avg() } }, //ts compiler complains
    aggregation: {value: ["value", avg()]},
  })
  .eventList().map(e => {
    return {
      timestamp: e?.timestamp().getTime(), 
      value: e?.get("value")
    }
  });

but the fixedWindowRollup returns that error:

TypeError: Cannot read properties of undefined (reading 'mid')
     at Index.timestamp (project/node_modules/pondjs/src/index.ts:89:32)
     at Event.timestamp (project/node_modules/pondjs/src/event.ts:578:30)
     at project/node_modules/pondjs/src/collection.ts:839:23
     at List.__iterate (project/node_modules/immutable/dist/immutable.js:3370:13)
     at List.forEach (project/node_modules/immutable/dist/immutable.js:4899:19)
     at SortedCollection.forEach (project/node_modules/pondjs/src/collection.ts:425:29)
     at SortedCollection.isChronological (project/node_modules/pondjs/src/collection.ts:837:14)
     at new SortedCollection (project/node_modules/pondjs/src/sortedcollection.ts:43:20)
     at project/node_modules/pondjs/src/windowedcollection.ts:177:51
     at project/node_modules/immutable/dist/immutable.js:2488:31
     at project/node_modules/immutable/dist/immutable.js:2506:18
btw I'm using syntax from version 1.0.0-alpha.0 because latest version didn't work with my ts compiler ...

I also posted the question fixedWindowRollup example needed as an issue directly to the repo but no luck so far unfortunately…
Thanks for any hint!