polycule-connect/polyculeconnect/static/scripts/index.js

const connectorNameKey = "connectorName";
const connectorIDParam = "connector_id";

const urlParams = new URLSearchParams(window.location.search);

function chooseConnector(connectorName) {
  let nextURL = new URL(window.location.href);
  nextURL.searchParams.append(connectorIDParam, connectorName);
  setState(STATE_IN_PROGRESS);
  window.location.href = nextURL;
}

// Clean the cache in case previous authentication didn't succeed
// in order not to get stuck in a login loop
function handleFailedState() {
  if (getState() !== STATE_SUCCESS) {
    localStorage.removeItem(connectorNameKey);
  }
}

// Add the connector name to local storage in case the auth succeeded
// and the remember-me box was checked
function handleSuccess(connectorName) {
  setState(STATE_SUCCESS);
  if (localStorage.getItem(rememberMeKey)) {
    localStorage.removeItem(rememberMeKey);
    localStorage.setItem(connectorNameKey, connectorName);
  }
}

function handleLoginPage() {
  handleFailedState();
  let connectorName = localStorage.getItem(connectorNameKey);
  if (getState() === STATE_SUCCESS && connectorName != null) {
    chooseConnector(connectorName);
  }
}

function goBackToLogin() {
  let nextURL = new URL(window.location.href);
  nextURL.searchParams.delete(connectorIDParam);
  window.location.href = nextURL;
}

if (window.location.pathname === "/authorize" && !urlParams.has(connectorIDParam)) {
  handleLoginPage();
}