JavaScript errors in Behat 3 + Mink 2 + Selenium 2

errors.js

/*
 * Include this file somewhere after in the top of your page.
 */
 
/**
 * @var Array List of all errors occurred.
 */
var errors = [];

/**
 * Add one error to the list of errors.
 */
function addError(error) {
    // Ensure error is an object, otherwise property access will fail.
    if (typeof(error) != "object") {
        return;
    }
    
    // Push an error on the stack.
    errors.push(error);
}

/**
 * Catch uncaught exceptions generated by JavaScript code.
 */
window.onerror = function(message, url, line, column, error) {
    addError({
        type: "javascript",
        message: message,
        location: url + ":" + line + ":" + column
    });
};

/**
 * Handle uncaught AJAX exceptions that are invoked via jQuery AJAX methods.
 */
$(document).ajaxError(function(event, xhr, settings, error) {
    addError({
        type: "xhr",
        url: settings.url,
        method: settings.type,
        message: error,
        statusCode: xhr.status,
        response: xhr.responseJSON ? xhr.responseText : null
    });
});

FeatureContext.php

<?php

use Behat\Behat\Hook\Scope\AfterStepScope;
use Behat\MinkExtension\Context\MinkContext;

class FeatureContext extends MinkContext 
{
    /**
     * Grab the JavaScript errors from the session. Only works in companion
     * with a global window variable `errors` that contains the JavaScript
     * and/or XHR errors.
     *
     * @AfterStep
     */
    public function takeJSErrorsAfterFailedStep(AfterStepScope $event)
    {
        $code = $event->getTestResult()->getResultCode();
        $driver = $this->getSession()->getDriver();
        
        if ($driver instanceof Selenium2Driver && $code === 99) {
            // Fetch errors from window variable.
            try {
                $json = $this->getSession()->evaluateScript("return JSON.stringify(window.errors);");
            } catch (\Exception $e) {
                // Ignore this exception, because this may be caused by the
                // driver and/or JavaScript.
                return;
            }
            
            // Unserialize the errors.
            $errors = json_decode($json);
            
            if (json_last_error() == JSON_ERROR_NONE) {
                $messages = [];
                
                foreach ($errors as $error) {
                    if ($error->type == "javascript") {
                        $messages[] = "- {$error->message} ({$error->location})";
                    } elseif ($error->type == "xhr") {
                        $messages[] = "- {$error->message} ({$error->method} {$error->url}): {$error->statusCode} {$error->response}";
                    }
                }
                
                printf("JavaScript errors:\n\n" . implode("\n", $messages));
            }
        }
    }
}

output.log

And some error happens
  Some error happened.
  Build info: version: '2.47.1', revision: '411b314', time: '2015-07-30 03:03:16'
  System info: host: 'VBox-van-BasilFX', ip: '127.0.1.1', os.name: 'Linux', os.arch: 'amd64', os.version: '3.19.0-28-generic', java.version: '1.8.0_45-internal'
  Driver info: driver.version: unknown (WebDriver\Exception\UnknownError)
│
│  JavaScript errors:
│  
│  - TypeError: this.getMaxChangeID is not a function (http://localhost:8000/js/index/changelist.js:36:21)
│
└─ @AfterStep

Thank you very much for this.