submit-social-housing-lettings-and-sales-data/app/frontend/cookie-banner.js

const cookieBannerEl = document.querySelector('.js-cookie-banner')

if (cookieBannerEl) {
  const cookieFormEl = document.querySelector('.js-cookie-form')

  cookieFormEl.addEventListener('click', (e) => {
    if (e.target.tagName !== 'BUTTON') {
      return
    }

    const body = new window.FormData(cookieFormEl)
    body.append('cookies_form[accept_analytics_cookies]', e.target.value)

    fetch(cookieFormEl.action, {
      method: 'PUT',
      headers: {
        Accept: 'application/json'
      },
      body
    })
      .then((res) => {
        if (res.status >= 200 && res.status < 300) {
          return res
        }

        throw new Error(res)
      })
      .then((res) => res.json())
      .then(({ message }) => {
        const messageEl = cookieBannerEl.querySelector('.js-cookie-message')
        messageEl.textContent = message

        cookieBannerEl
          .querySelector('.js-cookie-banner__form')
          .setAttribute('hidden', '')
        cookieBannerEl
          .querySelector('.js-cookie-banner__success')
          .removeAttribute('hidden')
      })

    const gaSrc = window.analyticsScript
    if (e.target.value === 'on' && gaSrc) {
      const scriptEl = document.createElement('script')
      scriptEl.src = gaSrc
      document.body.appendChild(scriptEl)
    }

    e.preventDefault()
  })

  const hideBannerEl = document.querySelector('.js-hide-cookie-banner')
  hideBannerEl.addEventListener('click', (e) => {
    e.preventDefault()

    cookieBannerEl.setAttribute('hidden', '')
  })
}