How to use the testcafe.Role function in testcafe

/// 
import { Role, Selector, t } from 'testcafe';

const userName = Selector('#user-name');

const someUser = Role('http://localhost:3000/fixtures/api/es-next/roles/pages/login-page.html', async() => {
    await t
        .typeText('input[name="name"]', 'SomeUser')
        .click('input[value="LogIn"]');
}, { preserveUrl: false });

fixture `AnonymousRole`
    .page `http://localhost:3000/fixtures/api/es-next/roles/pages/index.html`;

test('Test1', async() => {
    await t
        .useRole(someUser)
        .expect(userName.textContent).eql('SomeUser')
        .useRole(Role.anonymous())
        .expect(userName.textContent).eql('');
});

import { Role, Selector, t } from 'testcafe';

// $ExpectError - string as Selector
Selector(123)
const userName = Selector('#user-name');

const someUser = Role('http://localhost:3000/fixtures/api/es-next/roles/pages/login-page.html', async() => {
    await t
        .typeText('input[name="name"]', 'SomeUser')
        .click('input[value="LogIn"]');
});

fixture `AnonymousRole`
    .page `http://localhost:3000/fixtures/api/es-next/roles/pages/index.html`;

test('Test1', async() => {
  await t
        .useRole(someUser)
        .expect(userName.textContent).eql('SomeUser')
        .useRole(Role.anonymous())
        .expect(userName.textContent).eql('');
})

import { Role } from 'testcafe';
import setup from './setup';

const user = 'normal';
const pass = 'zhu88jie';

const normalRole = Role(setup.getPageUrl('login'), async t => {
  await t
    .typeText('input[name=username]', user)
    .typeText('input[name=password]', pass)
    .click('button[type=submit]');
});

// workaround
// https://testcafe-discuss.devexpress.com/t/running-multiple-tests-on-already-authenticated-session-browser-app/160/7
const fixCookie = () => {
  let role = 'normal',
    now = Date.now(),
    domain = 'localhost'; // fix domain when in docker env

  document.cookie = `user=${user}; path=/; domain=${domain}`;
  document.cookie = `role=${role}; path=/; domain=${domain}`;
  document.cookie = `last_login=${now}; path=/; domain=${domain}`;

export const createRegularUser = (login = 'a@a', password = 'a') => {
    return Role(resolveUrl('/signin'), async() => {
        await t.eval(() => window.localStorage.clear());

        // Disable "Getting started" modal.
        await t.eval(() => window.localStorage.showGettingStarted = 'false');
        await page.login(login, password);
    });
};

import {Selector, Role} from 'testcafe';
import {ReactSelector} from 'testcafe-react-selectors';
import checkPropTypes from '../checkPropTypes';

import Page from './pageModel';

const subSection = name => console.log('\x1b[33m%s\x1b[0m', ' - ' + name);

/* global fixture:true */
/* eslint babel/new-cap: 0 */

const page = new Page();

const adminUrl = 'http://127.0.0.1:8081/neos!';

const adminUser = Role(adminUrl, async t => {
    await t
        .typeText('#username', 'admin')
        .typeText('#password', 'password')
        .click('button.neos-login-btn');
}, {preserveUrl: true});

async function waitForIframeLoading(t) {
    await t.expect(ReactSelector('Provider').getReact(({props}) => {
        const reduxState = props.store.getState();
        return !reduxState.ui.contentCanvas.isLoading;
    })).ok('Loading stopped');
}

async function discardAll(t) {
    await t
        .click(ReactSelector('PublishDropDown ContextDropDownHeader'))

import { Role } from 'testcafe'

require('dotenv').config()

export const baseURL = process.env.E2E_TESTING_URL

export const admin = Role(`${baseURL}/wp-login.php`, async t => {
  await t
    .wait(100)
    .typeText('#user_login', 'admin', { paste: true })
    .typeText('#user_pass', 'password', { paste: true })
    .click('#wp-submit')
})

import { Selector, Role } from 'testcafe'
const testTime = Math.floor(new Date() / 1000)

const testUser = Role('http://localhost:8080/#/login', async t => {
  const mailField = Selector('div').withText('E-mail').child('input')
  const passwordField = Selector('div').withText('Password').child('input')
  await t
    .selectText(mailField)
    .typeText(mailField, `user${testTime}@example.com`)
    .selectText(passwordField)
    .typeText(passwordField, 'user')
    .pressKey('enter')
})

fixture('homepage')
  .page('http://localhost:8080/')

test('create user', async t => {
  await t
    .click(Selector('button').withText('SIGN UP!'))

await testController.navigateTo(githubPage.github.url());
});

When(/^I am typing my search request "([^"]*)" on GitHub$/, async function(text) {
    await testController.typeText(githubPage.github.searchButton(), text);
});

Then(/^I am pressing (.*) key on GitHub$/, async function(text) {
    await testController.pressKey(text);
});

Then(/^I should see that the first GitHub\'s result is (.*)$/, async function(text) {
    await testController.expect(githubPage.github.firstSearchResult().innerText).contains(text);
});

const gitHubRoleForExample = Role(githubPage.github.url() + 'login', async function(t) {
    await t
        .click(githubPage.github.loginButton())
        .expect(githubPage.github.loginErrorMessage().innerText).contains('Incorrect username or password.');
});

Then(/^I am trying to use (.*)$/, async function(text) {
    await testController.useRole(gitHubRoleForExample);
});

import { Role } from 'testcafe';

import { api } from './api';
import { containerContents } from './page-object/editor/container-contents';
import { login } from './page-object/login';

export const Admin = Role(
    `${api.baseUrl()}/#/login`,
    async t => {
        await login('admin', 'admin');
        await containerContents.expectVisible();
    },
    {
        preserveUrl: false
    }
);