gets the aspect ratio. Leaves a bit to be wanted.

aspectRatio.js

const aspectRatio = (height, width, seperator=':')=> {
  const gcd = (a, b) => b === 0 ? a : gcd(b, a % b)
  const [h1, w1] = height < width ? [width, height] : [height, width]
  const divisor = gcd(h1, w1)
  return `${h1/divisor}${seperator}${w1/divisor}`
}


console.log(aspectRatio(549,500)) // 549:500
console.log(aspectRatio(1024,768)) // 4:3
console.log(aspectRatio(533,320)) //533:320
console.log(aspectRatio(1106,2048)) // 1024:553
console.log(aspectRatio(100,100)) // 1:1
console.log(aspectRatio(533,320)) //533:320