// pure functions
const getPercent = (array) => {
  const maxValue = Math.max(...array)
  return array.map((n) => (n/maxValue) * 100 )
}
// [100, 40, 20]

// use
const setPercents = (objects) => {
  const values = objects.map(o => o.value)
  const percents = getPercent(values)
  return objects.map((object, index) => ({...object, percent: percents[index]}) )
}

setPercents([ {type: "critic", value: 25}, {type: "medium", value: 10}, {type: "low", value: 5} ])
// [ {type: "critic", value: 25, percent: 100}, {type: "medium": 10, percent: 40}, {type: "low", value: 5, percent: 20} ]