nl_tokens: Change the key for an existing item in the collection . If the old key does not exist this is a no - op .
pl_tokens: function ( oldKey , newKey ) { var me = this , map = <mask> . map , indexMap = me . indexMap , index = me . indexOfKey ( oldKey ) , item ; if ( index > - 1 ) { item = map [ oldKey ] ; delete map [ oldKey ] ; delete indexMap [ oldKey ] ; map [ newKey ] = item ; indexMap [ newKey ] = index ; me . keys [ index ] = newKey ; me . generation ++ ; } }