makeAssetCachePath v1

makeAssetCachePath.v1.js

/* from https://github.com/segment-boneyard/hash-mod/blob/master/lib/index.js */
function integerHash(string) {
  return (string + "").split("").reduce((memo, item) => {
    return (memo * 31 * item.charCodeAt(0)) % 982451653;
  }, 7);
}

function makeAssetCachePath(cacheDir, cacheKey) {
  const hash = crypto
    .createHash("sha256")
    .update(cacheKey)
    .digest("hex");

  const quotient = Math.floor(integerHash(hash) / 0x1000);
  const bucket1 = integerHash(hash) % 0x1000;
  const bucket2 = quotient % 0x1000;

  const bucket1HexString = sprintf("%x", bucket1);
  const bucket2HexString = sprintf("%x", bucket2);

  return {
    dir1: bucket1HexString,
    dir2: bucket2HexString,
    path: path.join(
      cacheDir,
      bucket1HexString,
      bucket2HexString,
      hash.toString()
    )
  };
}