[Solved]-How do I add a click event to a directed graph using dagre d3.js(javascript library)?-d3.js

I see that you've overridden functionality to add class selector, you can add click event handler similarly, see the following example.

    // Override drawNodes to set up the click.
    var oldDrawNodes = renderer.drawNodes();
    renderer.drawNodes(function(g, svg) {
      var svgNodes = oldDrawNodes(g, svg);

      // on click event handler
      svgNodes.on('click', function(d) { console.log('Clicked on node - ' + d); });

      return svgNodes;
    });

for adding click event handler for edges, try something like below given code

    var oldDrawEdges = renderer.drawEdgePaths();
    renderer.drawEdgePaths(function(g, svg) {
        var edges = oldDrawEdges(g, svg);
        edges.on('click', function (edgeId) { alert('Clicked on - ' + edgeId);});
        return edges;
    });