Converting cm to inches to nearest 1/16th inch

convert.js

// The company I work for creates custom acrylic cases based on customer's inputted dimensions.
// For fabrication our dimensions go down to the nearest 1/16th inch.
// International customers may use cm (or mm) and this is a program that will attempt to convert cm to inches
// down to the nearest 16th of an inch and display the result as a reduced fraction.

// 1 cm is equivalent to 0.39370 inches.

// EXAMPLE: 16.4 cm = 6 7/16 inches
// EXAMPLE: 10.5 cm = 4 2/16 or 4 1/8 inches

const CM_TO_INCHES = 0.39370;

// convert centimeter to inches (5 decimal places)
var centimetersToInches = function(centimeters) {
  var inches = centimeters * CM_TO_INCHES;
  return inches.toFixed(5);
};

// split converted inches into everything before the decimal and everything after the decimal
var before = function(n) {
  return Math.floor(n);
};

var after = function(n) {
  var fraction = n.toString().split('.')[1];
  return parseInt(fraction, 10);
};

// convert the "after" to the nearest 1/16th inch
var nearest16th = function(n) {
  var denominator = 16;
  var numerator = Math.round(16 * (n * 0.00001));
  // reduce the fraction
  while (numerator % 2 === 0) {
    numerator /= 2;
    denominator /= 2;
  }
  return numerator + "/" + denominator;
}

console.log(before(centimetersToInches(10.3)) + " "
+ nearest16th(after(centimetersToInches(10.3))) + " inches");

nearest16th has an infinite loop bug, try: nearest16th(after(centimetersToInches(60)))
Need to add protection to when numerator is 0:

var nearest16th = function(n) {
  var denominator = 16;
  var numerator = Math.round(16 * (n * 0.00001));
  // reduce the fraction
  while (numerator && numerator % 2 === 0) {
    numerator /= 2;
    denominator /= 2;
  }
  return numerator + "/" + denominator;
}