Selenium 的 driver.get() 在函数组合下不起作用

Question

driver.get(url)当我尝试将它与其他函数组合时，调用会导致错误。这是我的小功能方法：

const webdriver = require('selenium-webdriver');
const By        = webdriver.By;
const R         = require('ramda');

// Load a webpage
const loadPage = url => driver => driver.get(url)

// Find an WebElement via some locator
const getElement = locator => driver => driver.findElement(method)

// Locator by name
const byName = name => By.name(name)

// Send a series of input keys to a WebElement
const sendKeys = keys => elem => elem.sendKeys(keys)

以下最小示例加载 Google，并向搜索栏写入一条消息。这有效：

// Navigate to the Google webpage
const loadGoogle = loadPage('http://google.com')

// Retrieve the search form element
const getSearchForm = getElement(byName('q'))

const driver = new webdriver.Builder().forBrowser('chrome').build();
loadGoogle(driver); // NOTE: I have to do this seperately -- cannot do it inside the composition

var app = R.compose(sendKeys('search input'), getSearchForm)
app(driver);

但我希望包含loadGoogle在函数组合中——它会更整洁，更“正确”。像这样：

var app = R.compose(sendKeys('search input'), getSearchForm, loadGoogle)
app(driver);

但我收到一个driver.findElement is not a function错误：

/Users/name/Desktop/functional-test.js:9
const getElement = locator => driver => driver.findElement(locator)
                                               ^

    TypeError: driver.findElement is not a function
        at driver (/Users/name/Desktop/functional-test.js:9:48)
        at /Users/name/node_modules/ramda/src/internal/_pipe.js:3:14
        at /Users/name/node_modules/ramda/src/internal/_pipe.js:3:27
        at /Users/name/node_modules/ramda/src/internal/_arity.js:5:45
        at Object.<anonymous> (/Users/name/Desktop/functional-test.js:28:1)
        at Module._compile (module.js:541:32)
        at Object.Module._extensions..js (module.js:550:10)
        at Module.load (module.js:458:32)
        at tryModuleLoad (module.js:417:12)
        at Function.Module._load (module.js:409:3)

我认为这是因为loadPage没有返回WebDriver实例，但我不确定，也不知道如何修复它。

Answer 1

你需要改变

const loadPage = url => driver => driver.get(url) 

到

const loadPage = url => driver => { driver.get(url) ; return driver; }

发生错误的原因driver.get(url)是返回一个承诺，而不是 WebDriver 实例。由于组合中的其他函数接受 WebDriver 实例作为参数，因此导致错误