let columns = ["name", "age", "weight"] //
let data = [["jack", 18, 50],["jenny", 22, 60]]
let arr = []
//
[
{"name": "jack","age": 18,"weight": 50},{"name": "jenny","age": 22,"weight": 60},{"name": "","age": 40,"weight": 110}
]
{"name": "Total", "age": 40, "weight": 110} the last one is the cumulative addition of age and weight to the array push