wolfram.js

wolfram.js

function evolve(state, rules) {
  return state.map((item, i) =>
    rules[(4 * (state[i - 1] || 0)) +
          (2 * item) +
          (1 * (state[i + 1] || 0))]
  );
}

function parseRules(input) {
  const rule = parseInt(input, 10);
  const base = Array(8).fill(0);
  return base.map((_, i) => (rule >> i) & 1);
}

function print(state) {
  const row = state.map(item => item === 1 ? '█' : ' ');
  console.log(row.join(''));
}

function animate(state, rules) {
  print(state);
  state = evolve(state, rules);
  setTimeout(() => animate(state, rules), 100);
}

const input = process.argv[2];
const rules = parseRules(input);
const state = new Array(process.stdout.columns).fill(0);
state[Math.floor(state.length / 2)] = 1;

animate(state, rules);