Custom text formatter for Label on ApexChart Js Library

I want to add custom text formatter (mainly currency) on the label of my chart, how do i do that? Here’s how my chart currently looks like

And here’s the code for generating the chart

withChart(ChartBuilder.get()
                .withType(Type.AREA)
                .withZoom(ZoomBuilder.get()
                        .withEnabled(false)
                        .build())
                .build())
                .withStroke(StrokeBuilder.get()
                        .withCurve(Curve.SMOOTH)
                        .build())
                .withGrid(GridBuilder.get()
                        .withRow(RowBuilder.get()
                                .withColors("#f3f3f3", "transparent")
                                .withOpacity(0.5).build()
                        ).build())
                .withXaxis(XAxisBuilder.get()
                        .withCategories(x)
                        .withTitle(TitleBuilder.get()
                                .withText("Total (Rp.)")
                                .build())
                        .withTickPlacement(TickPlacement.BETWEEN)
                        .build())
                .withSeries(doubleSeries);

Sorry if this is not really about flow but more of library, but many thanks!