find scales

scales.js

let values = [{
  nation: 'USA',
  value: 150
}, {
  nation: 'EU',
  value: 75
}, {
  nation: 'China',
  value: 53
}];

let nums = values.map(num => num.value);

/*
 * the upper is the list maximum value
 */
function formula (list, scale = 100) {
  let maxVal = Math.max.apply(null, list);

  return list.map(item => {
    return item / maxVal * scale;
  });
}

/*
 * the upper bound is the sum of all the elements in the  list
 */
function formula2 (list, scale = 100) {
  let maxVal = list.reduce((a, b) => a + b);
  
  return list.map(item => {
    return item / maxVal * scale;
  })
}

console.log(formula(nums));
console.log(formula2(nums));