Update index.js

Author: Kikobeats

index.js

@@ -2,13 +2,14 @@
 const { gcd, highestFirst, formatAspectRatio } = require('./utils')
 
 module.exports = (height, width, seperator = ':') => {
-  if (isNaN(Number(height))) {
+  if (typeof height !== 'number') {
     throw new Error(`Invalid height: ${height}`)
   }
 
-  if (isNaN(Number(width))) {
+  if (typeof width !== 'number') {
     throw new Error(`Invalid width: ${width}`)
   }
+  
   const [h, w] = highestFirst(height, width)
   const divisor = gcd(h, w)
   return formatAspectRatio(h, w, divisor, seperator)