React Google Analytics with GDPR consent

analytics.js

import ua from 'universal-analytics';
 
const TRACKING_ID = 'UA-XXXXXXXXX-X';

let visitor;
 
export function init() {
  const isDev = !process.env.NODE_ENV || process.env.NODE_ENV === 'development';

  if (!isDev) {
    visitor = ua(TRACKING_ID);
  }
}
 
export function sendEvent(...args) {
  if (!visitor) { // noop
    return;
  }

  visitor.event(...args)
}
export function sendPageView(...args) {
  if (!visitor) { // noop
    return;
  }
  visitor.pageview(...args);
}

AppWithAnalytics.js

import React from 'react';
import CookieConsent, { Cookies } from 'react-cookie-consent';
import useAnalytics from './use-analytics';

const App = () => {
  const { sendPageView } = useAnalytics();
  
  useEffect(() => {
    sendPageView('/'); // should noop if consent not given (as visitor object is not initialised)
  }, [sendPageView])
  
  return (
    <CookieConsent
      location="bottom"
      buttonText="Agree"
      onAccept={() => {
        Cookies.set('cookie_consent', JSON.stringify({ essential: true, analytics: true }));
      }}
      onDecline={() => {
        Cookies.set('cookie_consent', JSON.stringify({ essential: true, analytics: false }));
      }}
      style={{ background: "#2B373B" }}
      buttonStyle={{ color: "#4e503b", fontSize: "13px" }}
      expires={365}
    >
      This website uses cookies to enhance the user experience.{" "}
      <span style={{ fontSize: "10px" }}>This bit of text is smaller :O</span>
    </CookieConsent>
    ...
  );
};

export default App;

use-analytics.js

import { useEffect } from 'react';
import CookieConsent, { Cookies } from "react-cookie-consent";

import { init, sendEvent, sendPageView } from './analytics';

const useAnalytics = () => {
  useEffect(() => {
    const consentCookieString = Cookies.get('cookie_consent');
    let consentCookie = {};
    try {
      consentCookie = JSON.parse(consentCookieString);
    } catch(err) {}
    
    if (consentCookie.analytics) {
      init();
    }
  }, []);
  
  return { sendEvent, sendPageView };
};