nl_tokens: Normalizes the view - sequence node so that the view - sequence is near to 0 .
pl_tokens: function _normalizePrevViewSequence ( scrollOffset ) { var count = 0 ; var normalizedScrollOffset = scrollOffset ; var normalizeNextPrev = false ; var node = this . _nodes . getStartEnumNode ( false ) ; while ( node ) { if ( ! node . _invalidated || ! node . _viewSequence ) { break ; } if ( normalizeNextPrev ) { this . _viewSequence = <mask> . _viewSequence ; normalizedScrollOffset = scrollOffset ; normalizeNextPrev = false ; } if ( ( node . scrollLength === undefined ) || node . trueSizeRequested || ( scrollOffset < 0 ) ) { break ; } scrollOffset -= node . scrollLength ; count ++ ; if ( node . scrollLength ) { if ( this . options . alignment ) { normalizeNextPrev = ( scrollOffset >= 0 ) ; } else { if ( Math . round ( scrollOffset ) >= 0 ) { this . _viewSequence = node . _viewSequence ; normalizedScrollOffset = scrollOffset ; } } } node = node . _prev ; } return normalizedScrollOffset ; }