Thank you @cchannon for the link. Its really helpful. However the snippet function provided by FullStory does not seem to work in the init method in PCF. Here is the code provided by them:
<script>
window['_fs_host'] = 'fullstory.com';
window['_fs_script'] = 'edge.fullstory.com/s/fs.js';
window['_fs_org'] = 'FEH9J';
window['_fs_namespace'] = 'FS';
(function(m,n,e,t,l,o,g,y){
if (e in m) {if(m.console && m.console.log) { m.console.log('FullStory namespace conflict. Please set window["_fs_namespace"].');} return;}
g=m[e]=function(a,b,s){g.q?g.q.push([a,b,s]):g._api(a,b,s);};g.q=[];
o=n.createElement(t);o.async=1;o.crossOrigin='anonymous';o.src='https://'+_fs_script;
y=n.getElementsByTagName(t)[0];y.parentNode.insertBefore(o,y);
g.identify=function(i,v,s){g(l,{uid:i},s);if(v)g(l,v,s)};g.setUserVars=function(v,s){g(l,v,s)};g.event=function(i,v,s){g('event',{n:i,p:v},s)};
g.anonymize=function(){g.identify(!!0)};
g.shutdown=function(){g("rec",!1)};g.restart=function(){g("rec",!0)};
g.log = function(a,b){g("log",[a,b])};
g.consent=function(a){g("consent",!arguments.length||a)};
g.identifyAccount=function(i,v){o='account';v=v||{};v.acctId=i;g(o,v)};
g.clearUserCookie=function(){};
g.setVars=function(n, p){g('setVars',[n,p]);};
g._w={};y='XMLHttpRequest';g._w[y]=m[y];y='fetch';g._w[y]=m[y];
if(m[y])m[y]=function(){return g._w[y].apply(this,arguments)};
g._v="1.3.0";
})(window,document,window['_fs_namespace'],'script','user');
</script>
