检查元素是否存在 - selenium/javascript/node-js

Question

我想在执行此行之前检查元素是否存在:

driver.findElement(webdriver.By.id('test'));

如果test文档中不存在id ,即使在try-block中,也会抛出错误"no such element" .我找到了Java的答案,您可以在其中检查大小是否为0,但在node-js中,这会在我检查大小之前抛出错误.

throw error; ^ NoSuchElementError: no such element

Answer 1

您可以利用可选的错误处理程序参数then().

driver.findElement(webdriver.By.id('test')).then(function(webElement) {
        console.log('Element exists');
    }, function(err) {
        if (err.state && err.state === 'no such element') {
            console.log('Element not found');
        } else {
            webdriver.promise.rejected(err);
        }
    });

我找不到它的文件中明确规定,但在确定这个从函数定义webdriver/promise.js中selenium-webdriver模块来源:

  /**
   * Registers a callback on this Deferred.
   * @param {Function=} opt_callback The callback.
   * @param {Function=} opt_errback The errback.
   * @return {!webdriver.promise.Promise} A new promise representing the result
   *     of the callback.
   * @see webdriver.promise.Promise#then
   */
  function then(opt_callback, opt_errback) {