refactor!: convert to Polymer 3

vaadin/vaadin-list-mixin#75

Author: web-padawan

packages/vaadin-list-mixin/.eslintrc.json

@@ -1,15 +1,15 @@
 {
-  "extends": "vaadin",
+  "extends": [
+    "eslint:recommended",
+    "plugin:prettier/recommended"
+  ],
+  "plugins": ["prettier"],
   "env": {
     "browser": true,
-    "node": true,
     "es6": true
   },
-  "plugins": [
-    "html"
-  ],
-  "globals": {
-    "Polymer": false,
-    "Vaadin": false
+  "parserOptions": {
+    "sourceType": "module",
+    "ecmaVersion": 2020
   }
 }

packages/vaadin-list-mixin/.github/workflows/sauce.yml

@@ -0,0 +1,28 @@
+name: sauce
+
+on:
+  push:
+    branches:
+      - '**'
+    tags-ignore:
+      - '*.*'
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+    if: "! contains(toJSON(github.event.commits.*.message), '[skip ci]')"
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: 12
+
+    - name: Install dependencies
+      run: npm install
+
+    - name: SauceLabs tests
+      env:
+        SAUCE_USERNAME: ${{ secrets.SAUCE_USERNAME }}
+        SAUCE_ACCESS_KEY: ${{ secrets.SAUCE_ACCESS_KEY }}
+      run: npm run test:sauce

packages/vaadin-list-mixin/.github/workflows/tests.yml

@@ -0,0 +1,22 @@
+name: tests
+
+on: [pull_request]
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: 12
+
+    - name: Install dependencies
+      run: npm install
+
+    - name: Lint JavaScript
+      run: npm run lint
+
+    - name: Unit tests
+      run: npm test

packages/vaadin-list-mixin/.gitignore

@@ -1,2 +1,3 @@
 bower_components
 node_modules
+coverage

packages/vaadin-list-mixin/.prettierrc

@@ -0,0 +1,6 @@
+{
+  "singleQuote": true,
+  "printWidth": 120,
+  "trailingComma": "none",
+  "htmlWhitespaceSensitivity": "strict"
+}

packages/vaadin-list-mixin/.stylelintrc

@@ -1,36 +1,29 @@
-![Bower version](https://img.shields.io/bower/v/vaadin-list-mixin.svg)
-[![Published on webcomponents.org](https://img.shields.io/badge/webcomponents.org-published-blue.svg)](https://www.webcomponents.org/element/vaadin/vaadin-list-mixin)
-[![Build Status](https://travis-ci.org/vaadin/vaadin-list-mixin.svg?branch=master)](https://travis-ci.org/vaadin/vaadin-list-mixin)
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/vaadin/web-components?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
-
 # vaadin-list-mixin
+
 `vaadin-list-mixin` is a mixin for `nav` elements, facilitating navigation and selection of childNodes.
 
+[![npm version](https://badgen.net/npm/v/@vaadin/vaadin-list-mixin)](https://www.npmjs.com/package/@vaadin/vaadin-list-mixin)
+[![Discord](https://img.shields.io/discord/732335336448852018?label=discord)](https://discord.gg/PHmkCKC)
+
 ## Running tests in browser
 
 1. Fork the `vaadin-list-mixin` repository and clone it locally.
 
-1. Make sure you have [npm](https://www.npmjs.com/) and [Bower](https://bower.io) installed.
-
-1. When in the `vaadin-list-mixin` directory, run `npm install` and then `bower install` to install dependencies.
-
-1. Make sure you have [polymer-cli](https://www.npmjs.com/package/polymer-cli) installed globally: `npm i -g polymer-cli`.
-
-1. Run `npm start`.
+1. Make sure you have [npm](https://www.npmjs.com/).
 
-1. Navigate to http://127.0.0.1:3000/components/vaadin-list-mixin/test/index.html
+1. When in the `vaadin-list-mixin` directory, run `npm install` to install dependencies.
 
+1. Run `npm test` to start the tests in Chrome.
 
-## Running tests from the command line
 
-1. Install [web-component-tester](https://www.npmjs.com/package/web-component-tester): `npm install -g web-component-tester`
+## Debugging tests in browser
 
-1. When in the `vaadin-list-mixin` directory, run `wct` or `npm test`
+1. Run `npm run debug`, then choose manual mode (M) and open the link in browser.
 
 
 ## Following the coding style
 
-We are using [ESLint](http://eslint.org/) for linting JavaScript code. You can check if your code is following our standards by running `npm run lint`, which will automatically lint all `.js` files as well as JavaScript snippets inside `.html` files.
+We are using [ESLint](http://eslint.org/) for linting JavaScript code. You can check if your code is following our standards by running `npm run lint`, which will automatically lint all `.js` files.
 
 
 ## Contributing