JSFiddle - React, Tailwind, and code Playground

HTML

<!--
To use this example, generate a v2 API key in your PagerDuty account
and update lines 1 and 2 with your API key and the escalation_policy_ids
-->

<h1>Who's on call for our team</h1>
<pre id="raw_output"></pre>

CSS

#raw_output {
  display: none;
}

JavaScript

api_key = "jeZuiVYQbpG8dsz7uw7W" 
escalation_policies = "escalation_policies?team_ids%5B%5D=PBSU8DD"

$.ajax({
    headers: {
      Accept: "application/vnd.pagerduty+json;version=2",
      Authorization: "Token token="+api_key
    },
    url: "https://api.pagerduty.com/oncalls?time_zone=UTC&"+escalation_policies,
    cache: false,
    success: function(json) {
    	display_oncall(json)
      console.log(json);

			//You'll probably want to remove this:
      $("#raw_output").append(JSON.stringify(json, null, '  '))
  	},
    error: function(data) {
    	alert("Error")
      console.log(data)
    }
  })

function display_oncall(json) {
	console.log("Displaying")
  console.log(json)
	$.each(json.oncalls, function(index, value ){
  	console.log(index)
    console.log(value)
    if(value.escalation_level == 1) {
  		$('body').append("<div><a href='"+value.user.html_url+"'>"+value.user.summary+" is on call for "+value.escalation_policy.summary+" (level "+value.escalation_level+")</div>")
      }
  })
}