code: function _initArray() {
      if (typeof Uint32Array !== 'undefined') {
          _bitrev = new Uint32Array(_n);
      } else {
          _bitrev = [];
      }
      if (typeof Float64Array !== 'undefined') {
          _cstb = new Float64Array(_n * 1.25);
      } else {
          _cstb = [];
      }
  }
docs: initialize the array (supports TypedArray)