.coffee

for seq in event.data["seq"]
  console.log "Request: " + seq
  fetch(new Request("/#{seq}", {mode: 'no-cors'})).then((response) ->
    console.log "after Request: " + seq
    caches.open(CACHE_NAME).then((cache) ->
      cache.put("/#{seq}", response)
    )
  ).catch((err) ->
    console.error(err)
  )