question: public void emitRetainedVars ( GenerateJsVisitor gen ) { if ( ! retainedVars . isEmpty ( ) ) { gen . out ( "var " ) ; boolean first = true ; for ( String varName : retainedVars ) { if ( ! first ) { gen . out ( "," ) ; } first = false ; gen . out ( varName ) ; } gen . endLine ( true ) ; retainedVars . clear ( ) ; } }
target:  Writes all retained variables to the output of the specified generator, then clears them. 