Retrieve the Payload data section of a JSON Web Token.

get-jwt-payload.js

function getJwtPayload(){
	//retrieve JsonWebToken from cookies
	var cookies = document.cookie.split(";"),
		jwt;
	for (cookie of cookies){
		var keyValue = cookie.trim().split('=');
		if (keyValue[0] === "jwt"){
			jwt = keyValue[1];
		}
	}

	//extract user data from JsonWebToken
	var payload = jwt.split('.')[1]; // middle section = payload
	var decodedPayload = JSON.parse(atob(payload));
	return decodedPayload['data'];
}