Mixpanel track_links does not work with dynamically added elements

Question

I'm having trouble using mixpanel.track_links with links added dynamically (after page load).

For a general example, given this page:

<div id="link-div"></div>
<input type="button" id="add-link" />
<script type="text/javascript">
mixpanel.track_links(".mixpanel-event", "event name", function(ele) { return { "type": $(ele).attr("type")}});
</script>

At some user action, links are added to the page using jquery. For example:

$('#add-link).click(function() {
    $('#link-div').html('<a class="mixpanel-event" type="event-type" href="#>Link to track</a>');
})

The problem is that track_links isn't triggered on click of the newly created link. I'm hoping someone can share their experience in enabling the track_link function to work for dynamically added links.

Answer 1

I was curious so I checked out their code and went ahead and did as they suggested. I tested it, and it worked fine. This requires jQuery though.

Example usage: mixpanel.delegate_links(document.body, 'a', 'clicked link');

// with jQuery and mixpanel
mixpanel.delegate_links = function (parent, selector, event_name, properties) {
    properties = properties || {};
    parent = parent || document.body;
    parent = $(parent);

    parent.on('click', selector, function (event) {
        var new_tab = event.which === 2 || event.metaKey || event.target.target === '_blank';

        properties.url = event.target.href;

        function callback() {
            if (new_tab) {
                return;
            }

            window.location = properties.url;
        }

        if (!new_tab) {
            event.preventDefault();
            setTimeout(callback, 300);
        }

        mixpanel.track(event_name, properties, callback);
    });
};

Answer 2

I had a somewhat hard time trying to get tracking links working as expected on react. The main caveat I noticed was that duplicated events may be sent to mixpanel in bursts. I used a slightly modified version of @Kyle to solve my problem. Additionally, this accounts for properties being possibly a function as supported by the mixpanel API.

// mixpanelSetup.js
import md5 from "md5";

const setup = () => {
  mixpanel.init(TOKEN);
  // Sets ensure unique items
  mixpanel.delegated_links = new Set();
  mixpanel.delegate_links = (parent, selector, eventName, eventProperties, {ignoreUrl=false}) => {
    // Hash by whatever thing(s) the use case considers 'unique' (e.g md5(`${selector}__${eventName}`))
    const linkHash = md5(selector);
    parent = parent || document.body;
    parent = $(parent);
    // Do not add additional trackers for an already tracked event.
    if (mixpanel.delegated_links.has(linkHash)) {
      return;
    }
    mixpanel.delegated_links.add(linkHash);
    parent.on("click", selector, (event) => {
      const newTab = event.which === 2 || event.metaKey || event.target.target === "_blank";
      if (typeof eventProperties === "function") {
        eventProperties = eventProperties(event.target) || {};
      }
      eventProperties.url = event.target.href;
      // In case we don't want the url on the properties.
      if (ignoreUrl) {
        delete eventProperties.url;
      }
      const callback = () => {
        if (newTab) {
          return;
        }
        window.location = event.target.href;
      };
      if (!newTab) {
        event.preventDefault();
        setTimeout(callback, 300);
      }
      console.debug("Tracking link click!");
      mixpanel.track(eventName, eventProperties, callback);
    });
  };
}

And can be used as:

// MyComponent.jsx
import React, { useEffect } from "react";
import { Link, useLocation } from "@reach/router";

const MyComponent = ({ moduleName, key, ...props }) => {
  const id = `#${id}__${moduleName}`;

  useEffect(() => {
    mixpanel.delegate_links(document.parent, id, event => {
      return {
          module: event.id.split("__").pop(),
          ...props.otherPropsToTrack
      };
    })
  }, [])

  return <>
    <Link {...props} to="/some/path" id={id}>My Page</Link>
  </>
}