colors util

colors.ts

export type RGBA = [number, number, number, number | undefined]

export const splitStringChunk = (string: string, size: number): string[] => {
  const re = new RegExp(".{1," + size + "}", "g")
  const maybeResult = string.match(re)
  return maybeResult ? maybeResult : []
}

export const hexToRGB = (hex: string): RGBA => {
  if (hex.length !== 3 && hex.length !== 6 && hex.length !== 8) {
    throw new Error("hex цвет не валидный")
  }
  const [R, G, B, maybeA] =
    hex.length === 3
      ? hex.split("").map((x) => parseInt(x.repeat(2), 16))
      : splitStringChunk(hex, 2).map((x) => parseInt(x, 16))
  return [R, G, B, maybeA]
}

export const parseRBGa = (RBGa: string): RGBA => {
  const resultParse = RBGa.match(/[\d\.]+/g)

  if (resultParse === null || resultParse.length < 3) {
    throw new Error("RBGa цвет не валидный")
  }

  const alphaIsNotDecimal = /%/.test(RBGa)

  const [R, G, B, maybeA] = resultParse
  let A: number | undefined
  if (alphaIsNotDecimal) {
    A = parseFloat(`.${maybeA}`)
  } else if (maybeA) {
    A = parseFloat(maybeA)
  }

  return [parseInt(R), parseInt(G), parseInt(B), A]
}

export const RGBToHax = (RBGa: string): string => {
  const [R, G, B, maybeA] = parseRBGa(RBGa)
  let hex = R.toString(16) + G.toString(16) + B.toString(16)
  if (maybeA) {
    hex += (maybeA * 255).toString(16)
  }
  return hex
}