Get bar value when onClick Reactjs

i am faceing a problem with reactjs using chartjs i want to get the value of Bar chart in chartjs 2 when clicking in the Bar i found this code but i didnt know how to use it on react

document.getElementById("myChart").onclick = function (evt) {
    var activePoints = myChart.getElementsAtEventForMode(evt, 'point', myChart.options);
    var firstPoint = activePoints[0];
    var label = myChart.data.labels[firstPoint._index];
    var value = myChart.data.datasets[firstPoint._datasetIndex].data[firstPoint._index];
    alert(label + ": " + value);
};