convert a number from old range to new range

rangeConvert.js

export function RangeConvertFactory({
  oldMin, oldMax, newMin, newMax
}) {
  const oldRange = oldMax - oldMin;
  const newRange = newMax - newMin;

  return (val) => (((val - oldMin) * newRange) / oldRange) + newMin;
}

// usage
const convert0to10TO5to10 = RangeConvertFactory({ oldMin: 0, oldMax: 10, newMin: 5, newMax: 10 });
for (let i=0; i<=10; i++) console.log(convert0to10TO5to10(i));
// 5
// 5.5
// 6
// 6.5
// 7
// 7.5
// 8
// 8.5
// 9
// 9.5
// 10