nl_tokens: In - place ( ie non - cloning ) object traversal .
pl_tokens: function traverseInPlace ( o , visitor ) { if ( _ . isArray ( o ) ) { var len = o . length ; for ( var i = 0 ; i < len ; ++ i ) { traverseInPlace ( o [ i ] , visitor ) ; visitor ( o , i ) ; } } else if ( _ . isPlainObject ( o ) ) { for ( var key in o ) { if ( ! o . hasOwnProperty ( key ) ) <mask> ; traverseInPlace ( o [ key ] , visitor ) ; visitor ( o , key ) ; } } return o ; }