babel-register/lib/node.js improved performance 10x

babel-regiser-lib-node.js

function compile(filename) {
  var result = undefined;

  var cacheKey = filename + ":" + babel.version;

  var env = process.env.BABEL_ENV || process.env.NODE_ENV;
  if (env) cacheKey += ":" + env;

  if (cache) {
    var cached = cache[cacheKey];
    if (cached && cached.mtime === mtime(filename)) {
      result = cached;
    }
  }

  if (!result) {
    var optsManager = new _babelCore.OptionManager();
    optsManager.mergeOptions(_lodashLangCloneDeep2["default"](transformOpts), "base", null, _path2["default"].dirname(filename));
    var opts = optsManager.init({ filename: filename });

    result = babel.transformFileSync(filename, _lodashObjectExtend2["default"](opts, {
      // Do not process config files since has already been done with the OptionManager
      // calls above and would introduce duplicates.
      babelrc: false,
      sourceMap: "both",
      ast: false
    }));
  }

  if (cache) {
    cache[cacheKey] = result;
    result.mtime = mtime(filename);
  }

  maps[filename] = result.map;

  return result.code;
}