Addressing an important caching issue

Unpoly 3.2.0 no longer cache responses with an empty body (fixes #497). In particular responses with 304 Not Modified are no longer cached when using conditional requests.

As this issue could cause errors when rendering, we recommend all Unpoly 3 users to upgrade.

Using the server response that closed an overlay

When an overlay closes in reaction to a server response, no content from that response is rendered.

Sometimes you do need to access the discarded response, e.g. to render its content in another layer.
For this you can now access response via the { response } property of the up:layer:accepted and up:layer:dismissed events.

For example, the link link opens an overlay with a form to create a new company (/companies/new).
After successful creation the form redirects to the list of companies (/companies). In that case
we can use the HTML from the response and render it into the parent layer:

<a href="/companies/new"
   up-layer="new"
   up-accept-location="/companies"
   up-on-accepted="up.render('.companies', { response: event.response }">
  New company
</a>

The { response } property is available whenever a server response causes an overlay to close:

• When a server-sent event matches a close condition.
• When the new location matches a close condition.
• When the server explicitly closes an overlay using an HTTP header.

Rendering up.Response objects

If you have manually fetched content from the server, you can now pass an up.Response object as a { response } option to render its contents:

let response = await up.request('/path')
up.render({ target: '.target', response })

The various ways to provide HTML to rendering functions are now summarized on a new documentation page.

Other changes

• You can now use [up-href] without also setting [up-follow] or [up-target] (fixes up-href in table row (tr) not working #489).

• Date inputs are again validated on change instead of blur.

  In Unpoly 3.0 this defaulted to blur because desktop date pickers emit a change event whenever the user changes a date component (day, month, year). Unfortunately this change caused issues with mobile date pickers as well as JavaScript date pickers (resolves up-validate on input[type=date] with flatpicker not working since 3.x #488, reverts [up-validate] on input[type=date] should run callback on blur event, not change event #336).

  If you prefer validating on blur, you can restore the behavior of Unpoly 3.0 by configuring up.form.config.watchChangeEvents.

• Rendering functions now have a better error message when referring to detached elements or when referring to non-existing layers.

• The results of up.Response#fragments are no longer cached to preserve memory.