omnichannel-frontend/src/shared/services/authFetch.js

import { API_BASE_URL } from './apiConfig';
import { clearSession } from '../../modules/auth/services/sessionService';

function getStoredToken() {
  return window.sessionStorage.getItem('authToken');
}

function shouldAttachToken(resource) {
  const url = typeof resource === 'string' ? resource : resource?.url;

  return Boolean(url && url.startsWith(API_BASE_URL) && getStoredToken());
}

export function installAuthFetchInterceptor() {
  window.localStorage.removeItem('authToken');
  window.localStorage.removeItem('authUser');

  const nativeFetch = window.fetch.bind(window);

  window.fetch = async (resource, options = {}) => {
    if (!shouldAttachToken(resource)) {
      return nativeFetch(resource, options);
    }

    const headers = new Headers(options.headers || {});

    if (!headers.has('Authorization')) {
      headers.set('Authorization', `Bearer ${getStoredToken()}`);
    }

    const response = await nativeFetch(resource, {
      ...options,
      headers,
    });

    if (response.status === 401) {
      clearSession();

      if (window.location.pathname !== '/login') {
        window.location.assign('/login');
      }
    }

    return response;
  };
}