title: hexToRGB tags: string,advanced

Converts a color code to a rgb() or rgba() string if alpha value is provided.

Split string by chunk of 2, filter blank string. convert to number

const hexToRGB = (hex: string) => {
  hex = hex.startsWith("#") ? hex.slice(1) : hex;
  if (hex.length === 3) {
    hex = Array.from(hex).reduce((str, x) => str + x + x, ""); // 123 -> 112233
  }
  const values = hex
    .split(/([a-z0-9]{2,2})/)
    .filter(Boolean)
    .map((x) => parseInt(x, 16));
  return `rgb${values.length == 4 ? "a" : ""}(${values.join(", ")})`;
};

const hexToRGB2 = (hex: string) => {
  let hexChars = Array.from(hex.startsWith("#") ? hex.slice(1) : hex);
  if (hexChars.length === 3) {
    hexChars = hexChars.reduce((str, x) => [...str, x, x], [] as string[]); // 123 -> 112233
  }
  const values = chunk(hexChars, 2).map(([v1, v2]) => parseInt(v1 + v2, 16));
  return `rgb${values.length == 4 ? "a" : ""}(${values.join(", ")})`;
};

hexToRGB("#27ae60ff"); // 'rgba(39, 174, 96, 255)'
hexToRGB("27ae60"); // 'rgb(39, 174, 96)'
hexToRGB("#fff"); // 'rgb(255, 255, 255)'

hexToRGB2("#27ae60ff"); // 'rgba(39, 174, 96, 255)'
hexToRGB2("27ae60"); // 'rgb(39, 174, 96)'
hexToRGB2("#fff"); // 'rgb(255, 255, 255)'