Can't transpile typescript due to d3 event error
<p>I have a d3 scatterplot chart in an Angular 2 project using typescript and webpack. Part of the chart responds to a mouseover event to display a tooltip. Now the mouseover event actually fires perfectly well, however I see an error when webpack transpiles the typescript.</p>

<pre><code> Property 'pageX' does not exist on type 'Event | BaseEvent'.
</code></pre>

<p>Here is a snippet showing the mouseover part of the chart element and the offending <code>d3.event.pageX</code>.</p>

<pre><code>  .on("mouseover", (d: any) =&gt; {
    if(d.roleName) {
      div.transition()
        .duration(200)
        .style("display", "block")
        .style("opacity", 1);
      div.html(d.roleName + "&lt;br/&gt;"  + d.org.name)
        .style("left", (d3.event.pageX) + "px")
        .style("top", (d3.event.pageY-80) + "px");
    }
  })
</code></pre>

<p>I am relatively new to typescript but gather the above issue may be something to do with the d3 typings file not mapping correctly?</p>

<p>Any guidance greatly appreciated.</p>