Convert RGB(A) to Hex(A)

RGBAToHexA.ts

interface RGBA {
  red: number
  green: number
  blue: number
  alpha?: number
}

const RGBAToHexA = ({ red, green, blue, alpha }: RGBA): string => {
  // We are using a system where 16 representations of value
  // exist (0-9, a-f) This will give us the hex representation
  // of 0-255, which is 256 total values.
  let redHex = red.toString(16)
  let greenHex = green.toString(16)
  let blueHex = blue.toString(16)
  let alphaHex

  // Handle instances where the hex value assigned
  // only has a single digit.
  if (redHex.length === 1) redHex = `0${redHex}`
  if (greenHex.length === 1) greenHex = `0${greenHex}`
  if (blueHex.length === 1) blueHex = `0${blueHex}`

  // If alpha is passed, then handle it and return a 9 digit hex
  if (alpha) {
    alphaHex = Math.round(alpha * 255).toString(16)

    if (alphaHex.length === 1) alphaHex = `0${alphaHex}`

    return `#${redHex}${greenHex}${blueHex}${alphaHex}`
  }
  // Else return a 6 digit hex
  return `#${redHex}${greenHex}${blueHex}`
}