const initial = [
  { key: '1', referrals: 0, cash_bon: 0 },
  { key: '2', referrals: 0, cash_bon: 0 },
  { key: '3', referrals: 0, cash_bon: 0 },
  { key: '4', referrals: 0, cash_bon: 0 },
  { key: '5', referrals: 0, cash_bon: 0 },
  { key: '6', referrals: 0, cash_bon: 0 },
  { key: '7', referrals: 0, cash_bon: 0 },
];

const calcRefer = (arr, referAmount) => {
  let tempCopy = [...initial]
  tempCopy[0].referrals = referAmount
  tempCopy[1].referrals = tempCopy[0].referrals * referAmount
  let tempIdx = 1
  
  return arr.map((el, idx) => {
    if(idx > 1){
    tempCopy[idx].referrals = tempCopy[0].referrals * tempCopy[tempIdx].referrals
    tempIdx++
    }
    return el
  })
}

const result = calcRefer(initial, 10)

console.log(result)