nl_tokens: jumpToPast : jump to requested index in past history
pl_tokens: function jumpToPast ( history , index ) { if ( index < 0 || index >= history . past . length ) return history ; const { past , future , _latestUnfiltered } = <mask> ; const newPast = past . slice ( 0 , index ) ; const newFuture = [ ... past . slice ( index + 1 ) , _latestUnfiltered , ... future ] ; const newPresent = past [ index ] ; return newHistory ( newPast , newPresent , newFuture ) ; }