function TaskRepartitionChart() { } TaskRepartitionChart.prototype.execute = function() { var metrics = $("#chart").data("metrics"); var columns = []; for (var i = 0; i < metrics.length; i++) { columns.push([metrics[i].column_title, metrics[i].nb_tasks]); } c3.generate({ data: { columns: columns, type : 'donut' } }); };