Convert 3 digits color to 6 digits color

JavaScript

const toFullHexColor = (color) =>
  `#${(color.startsWith('#') ? color.slice(1) : color)
    .split('')
    .map((c) => `${c}${c}`)
    .join('')}`

TypeScript

const toFullHexColor = (color: string): string =>
  `#${(color.startsWith('#') ? color.slice(1) : color)
    .split('')
    .map((c) => `${c}${c}`)
    .join('')}`

Examples

toFullHexColor('123') // '#112233'
toFullHexColor('#123') // '#112233'
toFullHexColor('#abc') // '#aabbcc'