Migrate from analytics.js to gtag.js

Author: iMattPro

styles/all/template/event/overall_header_stylesheets_after.html

@@ -1,18 +1,16 @@
 {% if GOOGLEANALYTICS_ID %}
-<script>
-	(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-	(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
-	m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
-	})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
+	<!-- https://developers.google.com/analytics/devguides/collection/gtagjs/migration -->
+	<!-- Global site tag (gtag.js) - Google Analytics -->
+	<script async src="https://www.googletagmanager.com/gtag/js?id={{ GOOGLEANALYTICS_ID }}"></script>
+	<script>
+		window.dataLayer = window.dataLayer || [];
+		function gtag(){dataLayer.push(arguments);}
+		gtag('js', new Date());
 
-	ga('create', '{{ GOOGLEANALYTICS_ID }}', 'auto');
-	{% if S_REGISTERED_USER -%}
-	ga('set', 'userId', {{ GOOGLEANALYTICS_USER_ID }});
-	{% endif -%}
-	{% if S_ANONYMIZE_IP -%}
-	ga('set', 'anonymizeIp', true);
-	{% endif -%}
-	{% EVENT phpbb_googleanalytics_alter_ga_requirements -%}
-	ga('send', 'pageview');
-</script>
+		gtag('config', '{{ GOOGLEANALYTICS_ID }}', {
+			{% EVENT phpbb_googleanalytics_gtag_options %}
+			{% if S_REGISTERED_USER %}'user_id': '{{ GOOGLEANALYTICS_USER_ID }}',{% endif %}
+			{% if S_ANONYMIZE_IP %}'anonymize_ip': true,{% endif %}
+		});
+	</script>
 {% endif %}