文字を共感覚に沿った色にする

kyokankaku-colored-char.js

color = {
  0: 'black',
  1: 'white',
  2: 'yellow',
  3: 'lightgreen',
  4: 'pink',
  5: 'blue',
  6: 'red',
  7: 'lightgreen',
  8: 'black',
  9: 'brown',
};
newhtml = $0.textContent.split('').map(c => `<span style="color: ${color[c] ? color[c] : 'inherit'}">${c}</span>`).join('');
$0.innerHTML = newhtml;