Get Color From Image

hexFromImage.js

function rgbToHex(r, g, b) {
  if (r > 255 || g > 255 || b > 255) throw 'Invalid color component'
  return ((r << 16) | (g << 8) | b).toString(16)
}

const generateColor = src => {
  return new Promise((res, rej) => {
    let c = document.createElement('canvas')
    if (c.getContext) {
      c = c.getContext('2d')

      const i = new Image()
      i.crossOrigin = 'Anonymous'

      i.onload = () => {
        c.drawImage(i, 0, 0)
        const p = c.getImageData(20, 20, 50, 50).data
        const hex = '#' + ('000000' + rgbToHex(p[0], p[1], p[2])).slice(-6)
        res(hex)
      }

      i.onerror = () => {
        rej('#003366')
      }

      i.src = src
    }
  })
}