refactored and simplified library. Added tests for utils

Author: michaelwclark

index.js

@@ -1,22 +1,8 @@
 'use strict'
+const { gcd, highestFirst, formatAspectRatio } = require('./utils')
 
-const gcd = (a, b) => b === 0 ? a : gcd(b, a % b)
-const isUndefined = value => typeof value === 'undefined'
-
-module.exports = (numerator, denominator, separator = ':') => {
-  let temp
-
-  if (numerator === denominator) return `1${separator}1`
-
-  if (numerator < denominator) {
-    temp = numerator
-    numerator = denominator
-    denominator = temp
-  }
-
-  const divisor = gcd(numerator, denominator)
-
-  return isUndefined(temp)
-    ? `${numerator / divisor}${separator}${denominator / divisor}`
-    : `${denominator / divisor}${separator}${numerator / divisor}`
+module.exports = (height, width, seperator = ':') => {
+  const [h, w] = highestFirst(height, width)
+  const divisor = gcd(h, w)
+  return formatAspectRatio(h, w, divisor, seperator)
 }