utils.js

export const calculateRgba = (input, opacity) => {
  let color
  if (input[0] === `#`) {
    color = input.slice(1)
  }

  if (color.length === 3) {
    let res = ``
    color.split(``).forEach(c => {
      res += c
      res += c
    })
    color = res
  }

  const rgbValues = color
    .match(/.{2}/g)
    .map(hex => parseInt(hex, 16))
    .join(`, `)
  return `rgba(${rgbValues}, ${opacity})`
}

export const range = (size, startAt = 0) =>
  [...Array(size).keys()].map(i => i + startAt)

export const characterRange = (startChar, endChar) =>
  String.fromCharCode(
    ...range(
      endChar.charCodeAt(0) - startChar.charCodeAt(0),
      startChar.charCodeAt(0)
    )
  )

export const zip = (arr, ...arrs) =>
  arr.map((val, i) => arrs.reduce((list, curr) => [...list, curr[i]], [val]))