src/Utl.js
function flatten(a) {
  function _reduce(a) { return a.reduce(_flatten, []); }

  function _flatten(a, b) {
    return a.concat(Array.isArray(b) ? _reduce(b) : b);
  }

  return _reduce(a);
}
function flatten(a) {
  function _reduce(a) { return a.reduce(_flatten, []); }

  function _flatten(a, b) {
    return a.concat(Array.isArray(b) ? _reduce(b) : b);
  }

  return _reduce(a);
}
function flatten ( a ) { function _reduce ( a ) { return a . reduce ( _flatten , [ ] ) ; } function _flatten ( a , b ) { return a . concat ( Array . isArray ( b ) ? _reduce ( b ) : b ) ; } return _reduce ( a ) ; }
Flatten an array.
Flatten an array .