let indexArr = [10,8,65,74,56,23]
let endIndexArr = indexArr.map(function (v: any, i: any, arr: any) { return v - ((i === 0) ? 0 : arr[i - 1]) }).slice(1)
// console.log(endIndexArr,'endIndexArr'); [-2, 57, 9, -18, -33] "endIndexArr"
let indexArr = [10,8,65,74,56,23]
let endIndexArr = indexArr.map(function (v: any, i: any, arr: any) { return v - ((i === 0) ? 0 : arr[i - 1]) }).slice(1)
// console.log(endIndexArr,'endIndexArr'); [-2, 57, 9, -18, -33] "endIndexArr"