Getting Value from a nested array in JavaScript [duplicate]

I’m trying to get a value from a nested array of objects in JavaScript.

report[i].rows[1].rows.[lenght - 1].cells[lenght - 2].value

I want this to return value from this below path.

report[i].rows[1].rows.[5].cells[4].value

But each report has different index for rows and cells. So

report[i].rows[1].rows.[last item].cells[second last item].value

I appreciate your responses. Thank you