click-function.js

//We first perform a selectAll on the circles of the SVG (i.e. the nodes of our graph)
//And if a node is clicked, we perform the function supplying that nodes values as an argument
svg.selectAll("circle").on("click", function(d){
  //We first create a string for the country's name of the node clicked
  let name = "Country: " + d.name.toUpperCase();
  //We then set up the exporters string
  let string = "Exporters: ";

  //From our predefined object containing key-value pairs of linked nodes we check to see what our node is linked to
  //To make the linkedByIndex object we iterated over the links of the graph and placed them in it
  Object.keys(linkedByIndex[d.index]).forEach(key => {
    for(n of graph.nodes) {
      //Sometimes we might not have parsed the data perfectly so we need to do some sanity checks
      if(n.index == key && n.name != undefined) {
        //If everything is code we add it to the string
        string += (n.name.toUpperCase() + ", ");
      }
    }
  });
  
  //And then manipulate the DOM using some vanilla JS
  let country = document.getElementById("country");
  country.innerHTML = name;

  let exporters = document.getElementById("exporters");
  exporters.innerHTML = string;
});