const ops = ["5", "2", "C", "D", "+"]

const intructionset = {
  "N": (n) => {
    return parseInt(n)
  },
  "+": (array) => {
    return [...array, array[array.length - 1] + array[array.length - 2]]
  },
  "D": (array) => {
    return [...array, array[array.length - 1] * 2]
  },
  "C": (array) => {
    return array.filter((ele, index) => index != array.length - 1)
  },
}


const record = ops.reduce((recordAccumulator, currentInstruction) => {
  if (currentInstruction !== 'D' && currentInstruction !== 'C' && currentInstruction !== '+') {
    return [...recordAccumulator, intructionset["N"](currentInstruction)]
  }
  return intructionset[currentInstruction](recordAccumulator)
}, []).reduce((sum, v) => sum + v, 0)



console.log(ops)
console.log(record)