Chart Js Legend onclick

var totalCount = 0;
var chart1 = new Chart(ctx1, {
.
.
.
options: {
title: {
display: true,
position: ‘bottom’,
text: ‘Total :’+ totalCount
},
legend: {
display: true,
},
}

});

chart1.options.legend.onClick = function (ev, legendItem) {
var index = legendItem.index;
var ci = this.chart;
var meta = ci.getDatasetMeta(0);
meta.data[index].hidden = meta.hidden === null ? !ci.data.datasets[0]._meta[ci.id].data[index].hidden : null;

                   ci.update();
                    ci.options.title.text = "Total :" + meta.total;
                }