Demos are all broken because data/contacts.json 404s

[lukebjerring]

Description

None of the demos load properly.
e.g. https://npm-demos.appspot.com/@polymer/iron-list@3.0.2/demo/grouping.html

Expected outcome

Demos show an iron-list of sorts

Actual outcome

None of the demos show a list because the data doesn't load

Live Demo

https://npm-demos.appspot.com/@polymer/iron-list@3.0.2/demo/grouping.html

Steps to reproduce

Open the example

Browsers Affected

Probably all; Only checked Chrome.

[keanulee]

Where did you find this the npm-demos.appspot.com link? I'm guessing it's because that service doesn't serve JSON files because they're definitely included in the published NPM package (https://unpkg.com/@polymer/iron-list@3.0.2/demo/data/contacts.json).

[lukebjerring]

https://www.webcomponents.org/element/@polymer/iron-list/demo/demo/index.html

From Google search, initially, the landing page is actually
https://www.webcomponents.org/element/polymerelements/iron-list

But the UI redirects it to the @polymer npm package. As a result, the (first) demo link doesn't work:
https://raw-dot-custom-elements.appspot.com/polymerelements/iron-list/v3.0.2/iron-list/demo/cards.html
That link is broken too, with

cards.html:1 Uncaught TypeError: Failed to resolve module specifier "@polymer/polymer/polymer-legacy.js". Relative references must start with either "/", "./", or "../".

Then, on a reload of the @polymer URL, there's a different issue (the one that I originally filed here).