Object Builder for the birds

peeps.js

let admins = [];
let speakers = [];
let listeners = [];

(function(open) {
	window.XMLHttpRequest.prototype.open = function() {
		this.addEventListener("readystatechange", function() {
			if (this.readyState == 4) {
				if (this.responseURL.includes('AudioSpaceById')) {
					let obj = JSON.parse(this.response);

					obj.data.audioSpace.participants.admins.forEach(function (item, index) {
						var admin_index = admins.findIndex(admin => admin.periscope_user_id == item.periscope_user_id);
						admin_index === -1 ? admins.push(item) : console.log("object already exists")
					});

					obj.data.audioSpace.participants.speakers.forEach(function (item, index) {
						var speaker_index = speakers.findIndex(speaker => speaker.periscope_user_id == item.periscope_user_id);
						speaker_index === -1 ? speakers.push(item) : console.log("object already exists")
					});

					obj.data.audioSpace.participants.listeners.forEach(function (item, index) {
						var listener_index = listeners.findIndex(listener => listener.periscope_user_id == item.periscope_user_id);
						listener_index === -1 ? listeners.push(item) : console.log("object already exists")
					});

					console.log(obj.data.audioSpace.participants);
				}
			}
		}, false);
		open.apply(this, arguments);
	};
})(window.XMLHttpRequest.prototype.open);