Polymer Hybrid

There are several breaking changes when upgrading from 1.0 to 2.0:

iron-lazy-page has been removed.

There are two reasons for this. First of all type extension is not supported by all major browsers.
It is therefore not possible to rely on <template is="..."> extensions.
Secondly, upgrading from iron-pages to iron-lazy-pages was quite intrusive
and the template syntax was confusing to users.

To upgrade, see the following example of before and after:

Before

<iron-lazy-pages attr-for-selected="data-route">
  <template is="iron-lazy-page" data-route="foo" path="foo.html">
    Foo page
  </template>
  <template is="iron-lazy-page" data-route="bar" path="bar.html">
    <bar-page></bar-page>
  </template>
</iron-lazy-pages>

After

<iron-lazy-pages attr-for-selected="data-route">
  <span data-route="foo" data-path="foo.html">Foo</span>
  <bar-page data-route="bar" data-path="bar.html"></bar-page>
</iron-lazy-pages>

As you can see, the templates are removed. Instead of path on iron-lazy-pages,
every page must now set data-path instead. This also removes compatibility for
plain text nodes (e.g. previously you could add plain text in a iron-lazy-page).
You must wrap the text in a <span> or <div> to once again display.

Paths are resolved relative to the parent of iron-lazy-pages

Given the following project structure:

src
 |-- pages-user.html
 |-- lazy-loaded.html

In 1.0 path="src/lazy-loaded.html". This has been changed to data-path="lazy-loaded.html". This is more logical from a usage perspective and also allows iron-lazy-pages to be used in reusable components where the absolute URL is not known for all applications.

Note: this works if iron-lazy-pages is a direct child of a custom element.

neon-lazy-pages has been removed

neon-animation has been deprecated and the maintenance burden of this element was too impactful for iron-lazy-pages. Moreover, numerous issues were raised regarding animation timing, animation inconsistency and therefore not living up to the expectations of developers. Thus I decided to remove the element, as it was not serving the purpose that it should have been and maintaining would be too costly for me.