Catch JS Errors with Playwright

Selenium has issues. I'm using it with Capybara and the latest encounter was a Net::ReadTimeout. I switched to Playwright following Justin Searls guide. One issue I encountered after the migration was that browser console logs were not accessible anymore with page.driver.browser.logs.get(:browser). We use them to fail tests on JavaScript errors. One solution is to record them from the Playwright page with an event handler. config.before(:each, type: :system, js: true) do |example| example.metadata[:js_console_messages] ||= [] Capybara.current_session.driver.with_playwright_page do |page| page.on('console', lambda { |msg| example.metadata[:js_console_messages]

Mar 26, 2025 - 12:34

Selenium has issues. I'm using it with Capybara and the latest encounter was a Net::ReadTimeout. I switched to Playwright following Justin Searls guide.

One issue I encountered after the migration was that browser console logs were not accessible anymore with page.driver.browser.logs.get(:browser). We use them to fail tests on JavaScript errors.

One solution is to record them from the Playwright page with an event handler.

config.before(:each, type: :system, js: true) do |example|
  example.metadata[:js_console_messages] ||= []
  Capybara.current_session.driver.with_playwright_page do |page|
    page.on('console', lambda { |msg|
      example.metadata[:js_console_messages] << {
        type: msg.type,
        text: msg.text,
        location: msg.location
      }
    })
  end
end

config.after(:each, type: :system, js: true) do |example|
  if example.metadata[:js_console_messages].present?
    aggregate_failures 'javascript console messages' do
      example.metadata[:js_console_messages].each do |msg|
        if msg[:type] == 'error'
          expect(msg[:text]).to be_nil, "JS Error: #{msg[:text]}"
        elsif msg[:type] == 'warning'
          warn "WARN: JS warning at #{msg[:location]}:\n#{msg[:text]}"
        end
      end
    end
  end
end

The output of a failed test will look like this:

The previous solution to simply look at page.driver.browser.logs.get(:browser) felt more natural to me. I'd be happy to receive a hint on how to catch JS errors in Ruby more nicely.