extractKeyFromJwtTokenPayload function
Extract the key from the JTW Token Payload
Implementation
int extractKeyFromJwtTokenPayload(String key, String token) {
final tokenBody = token.split('.')[1];
final stringToBase64 = utf8.fuse(base64);
final decoded = stringToBase64.decode(addCharsUntilMultipleOfFour(tokenBody));
final map = json.decode(decoded);
return map[key];
}