λ> main
*** Exception: FailedCommand JavascriptError
Session: SessionId "792d1038dc4363946fbee5d88b0044b3" at "localhost":4444
org.openqa.selenium.JavascriptException: javascript error: Cannot redefine property: languages
  (Session info: chrome=76.0.3809.100)
Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:25:53'
System info: host: 'I7', ip: '10.8.0.1', os.name: 'Windows 10', os.arch: 'x86', os.version: '10.0', java.version: '1.8.0_201'
Driver info: driver.version: unknown


import Test.WebDriver
import Test.WebDriver.JSON (ignoreReturn)
import Test.WebDriver.Session
import Control.Monad.IO.Class
import Data.Aeson.Types

chromecfg :: WDConfig
chromecfg = useBrowser chrome defaultConfig
            { wdHost           = "localhost"
            , wdPort           = 4444
            , wdHTTPRetryCount = 50
            , wdCapabilities   = caps
            }
  where
    caps :: Capabilities
    caps = defaultCaps { javascriptEnabled = Just False}

main :: IO WDSession
main = do
  s <- runSession chromecfg getSession
  runWD s $ do
    let js = "Object.defineProperty(navigator, 'languages', {get: function() {return ['foo', 'bar'];}, });"
    ignoreReturn $ executeJS [] js
    ignoreReturn $ executeJS [] js
    liftIO . print =<< (executeJS [] "navigator.languages" :: WD Value)

  return s