How many tries it takes to roll a particular sequence

roll.js

'use strict';

const roll = pattern => {
  const samples = [];
  let counter = 0;
  for(;;){
    if (samples.length >= pattern.length) {
      samples.shift();
    }
    const sample = Math.floor(Math.random() * 6) + 1;
    samples.push(sample);
    ++counter;
    compare: if (samples.length >= pattern.length) {
      for(let i = 0; i < pattern.length; ++i) {
        if (pattern[i] !== samples[i]) break compare;
      }
      break;
    }
  }
  return counter; // we got our sequence
};

const time = (pattern, n = 1000000) => {
  const start = Date.now();
  let averageRolls = 0;
  for (let i = 0; i < n; ++i) {
    const rolls = roll(pattern);
    averageRolls += rolls / n;
  }
  const duration = Date.now() - start;
  console.log(`${n} trials in ${duration / 1000}s looking for [${pattern.join(', ')}]`);
  console.log(`Average number of rolls: ${averageRolls}`);
};

time([4, 5, 6]);