Adding Google Analytics to React

I am trying to add Google Analytics to a React Web Application.

I know how to do it in HTML/CSS/JS sites and I have integrated it in an AngularJS app too. But, I'm not quite sure how to go about it when it comes to react.

With HTML/CSS/JS, I had just added it to every single page.

What I had done with AngularJS was adding GTM and GA script to index.html and added UA-labels to the HTML divs (and buttons) to get clicks.

How can I do that with React?

Please help!

Update: Feb 2019
As I saw that this question is being searched a lot, I decided to expand my explanation.
To add Google Analytics to React, I recommend using React-GA.
Add by running:
npm install react-ga --save

Initialization:
In a root component, initialize by running:

import ReactGA from 'react-ga';
ReactGA.initialize('Your Unique ID');

To report page view:

ReactGA.pageview(window.location.pathname + window.location.search);

To report custom event:

ReactGA.event({
  category: 'User',
  action: 'Sent message'
});

More instructions can be found in the github repo

---

The best practice for this IMO is using react-ga. Have a look at the github rep

If you prefer not to use a package this is how it can work in a react application. Add the "gtag" in index.html

<!-- index.html -->

<script>
            window.dataLayer = window.dataLayer || [];
            function gtag() {
                dataLayer.push(arguments);
            }
            gtag("js", new Date());

            gtag("config", "<GA-PROPERTYID>");
        </script>

In the submit action of the login form, fire off the event

window.gtag("event", "login", {
            event_category: "access",
            event_label: "login"
        });

Without using a package this is how I would do it:

In your index.js (in the render method):

    {/* Global site tag (gtag.js) - Google Analytics */}
    <script
      async
      src="https://www.googletagmanager.com/gtag/js?id=YOUR_TRACKING_ID"
    />
    <script>{injectGA()}</script>

And outside the class:

const injectGA = () => {
  if (typeof window == 'undefined') {
    return;
  }
  window.dataLayer = window.dataLayer || [];
  function gtag() {
    window.dataLayer.push(arguments);
  }
  gtag('js', new Date());

  gtag('config', 'YOUR_TRACKING_ID');
};

One other great library that you can check is redux-beacon.

It gets integrated very easily with react/redux application and has a great documentation for it. ReactGA is good too but with redux-beacon, you won't clutter your app code with google analytics code as it works via its own middleware.

Escape the analytics code with dangerouslySetInnerHTML

First you have of course to share the header code to all pages, e.g. as asked at: https://stackoverflow.com/questions/38510111/react-js-do-common-header

Then, this Next.js answer https://stackoverflow.com/a/24588369/895245 gives a good working code that should also work outside of Next.js. It escapes the analytics code with dangerouslySetInnerHTML:

  <script async src="https://www.googletagmanager.com/gtag/js?id=UA-47867706-3"></script>
  <script
    dangerouslySetInnerHTML={{
      __html: `window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'UA-47867706-3', { page_path: window.location.pathname });
`,
    }}
  />

where you should replace UA-47867706-3 with your own code.

This code is exactly the code that Google gives, but with the following modification: we added the:

{ page_path: window.location.pathname }

to gtag('config' for it to be able to get the visited path, since this is a JavaScript SPA.

This generates the desired output on the browser:

<script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-47867706-3"></script><script>window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'UA-47867706-3', { page_path: window.location.pathname });
</script>

The only other divergence from the exact code given by Google is the async="" vs async, but both of those are equivalent in HTML since it is a boolean attribute, see also: https://stackoverflow.com/questions/7851868/whats-the-proper-value-for-a-checked-attribute-of-an-html-checkbox/24588369#24588369

Escaping with dangerouslySetInnerHTML is necessary because otherwise React interprets the code inside script a JSX and that fails with:

Syntax error: Unexpected token, expected "}"

  21 |           <script>
  22 |             window.dataLayer = window.dataLayer || [];
> 23 |             function gtag(){dataLayer.push(arguments);}
     |                                                      ^
  24 |             gtag('js', new Date());
  25 |
  26 |             gtag('config', 'UA-47867706-3');

I wish they would just automatically escape stuff inside script for us.

Finally to get page switches, you also have to track that with more code, see the Next.js answer mentioned above for an example.

Related: https://stackoverflow.com/questions/34424845/adding-script-tag-to-react-jsx

Tested on react 17.0.2, next.js 10.2.2.

I suggest embedding the Segment script into your index.html, use the analytics library that is accessible on the window object, and add tracking calls onto React’s event handlers:

export default class SignupButton extends Component {
  trackEvent() {
    window.analytics.track('User Signup');
  }

  render() {
    return (
      <button onClick={this.trackEvent}>
        Signup with Segment today!
      </button>
    );
  }
}

I’m the maintainer of https://github.com/segmentio/analytics-react. I recommend checking it out if you want to solve this problem by using one singular API to manage your customer data, and be able to integrate into any other analytics tool (we support over 250+ destinations) without writing any additional code. 

Looking at google's site https://developers.google.com/analytics/devguides/collection/analyticsjs,

you could also add Google Analytics using this function:

const enableGA = () => {
  !function(A,n,g,u,l,a,r){A.GoogleAnalyticsObject=l,A[l]=A[l]||function(){
  (A[l].q=A[l].q||[]).push(arguments)},A[l].l=+new Date,a=n.createElement(g),
  r=n.getElementsByTagName(g)[0],a.src=u,r.parentNode.insertBefore(a,r)
  }(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

  ga('create', 'UA-XXXXXXXX-X');
  ga('send', 'pageview');
}

This way you don't need an external library, and it's pretty quick to setup.