Chart Tooltips for report

I’m trying to define a chart for a report and it’s working everything except for the Tooltips, can anyone indicate how to use the Tooltips for the reports code?

My chart code inside the “report”.py file:

chart = {
	'title': _("Monthly Balance"),
	'data': {
		'labels': [item[0] for item in sorted_chart_data],
		'datasets': [
			{'name': _("Balance"), 'values': [item[1] for item in sorted_chart_data]}
	'chart_type': "line",
	'lineOptions': {
		'dotSize': 6,
	'isNavigable': True,
	'tooltipOptions': {
		'formatTooltipX': "d => print_currency(d)",
		'formatTooltipY': "d => print_currency(d)"

“print_currency” function defined in the “report”.js file as follows:

function print_currency(value) {
	return value + " test"


I also tried the following configuration without succed…

'tooltipOptions': {
	'formatTooltipY': "function test(i) {return i + ' test';}"