compare-hash-performance.js

function compareHashPerformance(input = 'body { margin: 0; padding: 0; }', iterations = 100000) {
  // FNV-1a Hash Function (with Base36 Encoding)
  function fnvHash(str) {
    let h = 0 ^ 0x811c9dc5;
    for (let i = 0; i < str.length; i++) {
      h ^= str.charCodeAt(i);
      h = (h * 0x01000193) >>> 0;
    }
    const letters = 'abcdefghijklmnopqrstuvwxyz';
    const base36 = '0123456789' + letters;
    let result = '';
    do {
      result = base36[h % 36] + result;
      h = Math.floor(h / 36);
    } while (h > 0);
    return result;
  }

  // djb2 Hash Function
  function djb2Hash(str) {
    let hash = 5381;
    for (let i = 0; i < str.length; i++) {
      hash = ((hash << 5) + hash + str.charCodeAt(i)) >>> 0;
    }
    return '_' + hash.toString(36);
  }

  // Benchmark FNV-1a hash
  const startFnv = performance.now();
  for (let i = 0; i < iterations; i++) {
    fnvHash(input);
  }
  const timeFnv = performance.now() - startFnv;

  // Benchmark djb2 hash
  const startDjb2 = performance.now();
  for (let i = 0; i < iterations; i++) {
    djb2Hash(input);
  }
  const timeDjb2 = performance.now() - startDjb2;

  console.log(`FNV-1a Hash: ${timeFnv.toFixed(2)} ms for ${iterations} iterations.`);
  console.log(`djb2 Hash: ${timeDjb2.toFixed(2)} ms for ${iterations} iterations.`);

  // Determine which is faster and calculate factor and percentage difference.
  if (timeFnv < timeDjb2) {
    const factor = timeDjb2 / timeFnv;
    const percentageFaster = (1 - timeFnv / timeDjb2) * 100;
    console.log(`FNV-1a hash is faster by a factor of ${factor.toFixed(2)} (approximately ${percentageFaster.toFixed(2)}% faster).`);
  } else if (timeFnv > timeDjb2) {
    const factor = timeFnv / timeDjb2;
    const percentageFaster = (1 - timeDjb2 / timeFnv) * 100;
    console.log(`djb2 hash is faster by a factor of ${factor.toFixed(2)} (approximately ${percentageFaster.toFixed(2)}% faster).`);
  } else {
    console.log('Both hash functions performed similarly.');
  }
}

// Run the comparison with default CSS rule input and 100,000 iterations.
compareHashPerformance('body { margin: 0; padding: 0; }', 10_000_000);