nl_tokens: Track that an item was removed from the tracked array .
pl_tokens: function ( index ) { var returnValue = - 1 , self = this ; this . _findOperation ( index , function ( operation , operationIndex , rangeStart , rangeEnd , seenInSubArray ) { if ( operation . type === RETAIN ) { returnValue = seenInSubArray + ( index - rangeStart ) ; } if ( operation . count > 1 ) { -- operation . count ; } else { self . _operations . splice ( operationIndex , 1 ) ; self . _composeAt ( operationIndex ) ; } } , function ( ) { throw new Ember . <mask> ( "Can't remove an item that has never been added." ) ; } ) ; return returnValue ; }