DataviewJS & Charts, how to get a cumulative line chart out of daily outcome values

I understood what you explained. And works properly.

What we did now is that we sum up the outcome of the day, fabulous. What I also wanted to achieve is to sum up the days themselves. Meaning I have a graph where I can see how the outcome affects the prior days. Adding up …

For instance:

day1.outcome: 1.4
day2.outcome: -0.5
day3.outcome: 2.4

On day2 I would have sum.value of day1 + day2
on day3, a sum.value of day1 + day2 + day3
and so on …

Err… I would have to create another hidden value for each day and reduce it again … I slowly can understand the language but far away from being able to “speak” it.

Can you give me another hint on this?