Check if element exists - selenium / javascript / node-js

The selected answer did not work as expected (err.state was undefined and a NoSuchElementError was always thrown) -- though the concept of using the optional callbacks still works.

Since I was getting the same error as the OP is referencing, I believe NoSuchElementError should be referenced when determining if the targeted element exists or not. As it's name implies is the error that is thrown when an element does not exist. So the condition in the errorCallback should be:

err instanceof webdriver.error.NoSuchElementError

So the complete code block would be as follows (I also am using async/await for those taking advantage of that syntax):

var existed = await driver.findElement(webdriver.By.id('test')).then(function() {
    return true;//it existed
}, function(err) {
    if (err instanceof webdriver.error.NoSuchElementError) {
        return false;//it was not found
    } else {
        webdriver.promise.rejected(err);
    }
});
//handle value of existed appropriately here

Why not just use the isElementPresent(locatorOrElement) method? here's a link to the code:

http://selenium.googlecode.com/git/docs/api/javascript/source/lib/webdriver/webdriver.js.src.html#l777

You can leverage the optional error handler argument of 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);
        }
    });

I couldn't find it explicitly stated in the documentation, but determined this from the function definition in webdriver/promise.js in the selenium-webdriver module source:

  /**
   * 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) {