React component for loading Segment's library

SegmentLoader.js

import React from 'react';
import { string } from 'prop-types';

class SegmentLoader extends React.Component {
  componentDidMount() {
    const { segmentWriteKey } = this.props;
    // Create a queue, but don't obliterate an existing one!
    const analytics = (window.analytics = window.analytics || []);
    // If the real analytics.js is already on the page return.
    // If no write key is provided return.
    if (analytics.initialize || !segmentWriteKey) return;
    // If the snippet was invoked already show an error.
    if (analytics.invoked) {
      if (window.console && console.error) {
        console.error('Segment snippet included twice.');
      }
      return;
    }
    // Invoked flag, to make sure the snippet
    // is never invoked twice.
    analytics.invoked = true;
    // A list of the methods in Analytics.js to stub.
    analytics.methods = [
      'trackSubmit',
      'trackClick',
      'trackLink',
      'trackForm',
      'pageview',
      'identify',
      'reset',
      'group',
      'track',
      'ready',
      'alias',
      'debug',
      'page',
      'once',
      'off',
      'on',
    ];
    // Define a factory to create stubs. These are placeholders
    // for methods in Analytics.js so that you never have to wait
    // for it to load to actually record data. The `method` is
    // stored as the first argument, so we can replay the data.
    analytics.factory = function(method) {
      return function() {
        var args = Array.prototype.slice.call(arguments);
        args.unshift(method);
        analytics.push(args);
        return analytics;
      };
    };
    // For each of our methods, generate a queueing stub.
    for (var i = 0; i < analytics.methods.length; i++) {
      var key = analytics.methods[i];
      analytics[key] = analytics.factory(key);
    }
    // Define a method to load Analytics.js from our CDN,
    // and that will be sure to only ever load it once.
    analytics.load = key => {
      // Create an async script element based on your key.
      var script = document.createElement('script');
      script.type = 'text/javascript';
      script.async = true;
      script.src =
        ('https:' === document.location.protocol ? 'https://' : 'http://') +
        'cdn.segment.com/analytics.js/v1/' +
        key +
        '/analytics.min.js';
      // Insert our script next to the first script element.
      var first = document.getElementsByTagName('script')[0];
      first.parentNode.insertBefore(script, first);
    };
    // Add a version to keep track of what's in the wild.
    analytics.SNIPPET_VERSION = '4.0.0';
    // Load Analytics.js with your key, which will automatically
    // load the tools you've enabled for your account. Boosh!
    analytics.load(segmentWriteKey);
    // Make the first page call to load the integrations. If
    // you'd like to manually name or tag the page, edit or
    // move this call however you'd like.
    analytics.page();
  }

  render() {
    return <div className="segment-loader" style={{ display: 'none' }} />;
  }
}

SegmentLoader.propTypes = {
  segmentWriteKey: string.isRequired,
};

export default SegmentLoader;