4.3 Error Handling

Link to 4.3 Error Handling copied to clipboard

How to work around errors you might receive when using axe DevTools for Web for WebDriverIO

Version 4.3.0 and above of the axe DevTools integrations use a new technique when calling AxeDevToolsWebdriverIO.analyze() which opens a new window at the end of a run. Many of the issues outlined in this document address common problems with this technique and their potential solutions.

Having an Out-of-date Driver

A common problem is having an out-of-date driver. To fix this issue make sure that your local install of geckodriver or chromedriver is up-to-date.

An example error message for this problem will include a message about switchToWindow.


(node:17566) UnhandledPromiseRejectionWarning: Error: Malformed type for "handle" parameter of command switchToWindow
Expected: string
Actual: undefined

Having Popup blockers enabled

Popup blockers prevent us from opening the new window when calling AxeDevToolsWebdriverIO.analyze(). The default configuration for most automation testing libraries should allow popups. Please make sure that you do not explicitly enable popup blockers which may cause an issue while running the tests.

AxeDevToolsWebdriverIO.setLegacyMode(legacy: boolean)

If for some reason you are unable to run the new AxeDevToolsWebdriverIO.analyze technique without errors, axe provides a new chainable method that allows you to run the legacy version of AxeDevToolsWebdriverIO.analyze. When using this method axe excludes accessibility issues that may occur in cross-domain frames and iframes.


AxeDevToolsWebdriverIO.setLegacyMode is deprecated and will be removed in v5.0. Please report any errors you may have while running AxeDevToolsWebdriverIO.analyze so that they can be fixed before the legacy version is removed.


const { AxeDevToolsWebdriverIO } = require('@axe-devtools/webdriverio');
const { remote } = require('webdriverio');

(async () => {
  const client = await remote({
    logLevel: 'error',
    capabilities: {
      browserName: 'chrome'

  await client.url('https://dequeuniversity.com/demo/mars/');

  const builder = new AxeDevToolsWebdriverIO({ client });
  try {
    const results = await builder
  } catch (e) {
    // do something with the error
  await client.deleteSession();