Can't able to add jsEvents (onClick)

[phpdvlp]

I'm trying to add onClick function on chart but it throws error
Setting unknown property: dosamigos\chartjs\ChartJs::jsVar

Here is code,
ChartJs::widget([
'type' => 'bar',
'jsVar' => 'BarChart',
'jsEvents' => [
'onclick' => new JsExpression('function(e) {
var activePoints = BarChart.getElementsAtEvent(e);
if (activePoints !== undefined && activePoints[0] !== undefined && activePoints[0]._index !== undefined) {
var selectedIndex = activePoints[0]._index;
console.log(this.data.labels[selectedIndex]);
}
}')
],
......