javascript - JS : Class extends value is not a function or null

Question

这就是我尝试使用 WebdriverIO 构建用于登录测试的第一个页面对象的方式

但我收到错误 ERROR: Class extends value #<Page> is not a function or null login.page.js 第 3 行.

我不明白，我做错了什么...路径或文件名是否错误？

/tests/specs/login.specs.js

var expect = require('chai').expect
var LoginPage = require('../pageobjects/login.page')

describe('login form', function () {
  it('should deny access with wrong creds', function () {
    LoginPage.open()
    LoginPage.username.setValue('foo')
    LoginPage.password.setValue('bar')
    LoginPage.submit()
    expect(LoginPage.flash.getText()).to.contain('Your username is invalid!')
  })
})

/tests/pageobjects/page

'use strict'
class Page {
  constructor() {
    this.title = 'My Page'
  }
  open(path) {
    browser.url('/' + path)
  }
}
module.exports = new Page()

/tests/pageobjects/login.page.js

'use strict'
var Page = require('./page')
class LoginPage extends Page {
  get username () { return browser.element('#username') }
  get password () { return browser.element('#password') }
  get form () { return browser.element('#login') }
  get flash () { return browser.element('#flash') }

  open () {
    super.open('login')
  }

  submit () {
    this.form.submitForm()
  }
}
module.exports = new LoginPage()

Answer 1

正如 Gerardo 所指出的，您正在导出该类的一个实例并记下该类本身。尝试以下更改:

/tests/pageobjects/page

module.exports = Page;

/tests/pageobjects/login.page.js

module.exports = LoginPage;

/tests/specs/login.specs.js

var LoginPage = new (require('../pageobjects/login.page'))();

或

var LoginPage = require('../pageobjects/login.page');
var instanceLoginPage = new LoginPage();