Merge pull request #47 from PolymerLabs/lit-next

Merge lit-next into master

.eleventy.cjs

@@ -2,8 +2,12 @@ const syntaxHighlight = require('@11ty/eleventy-plugin-syntaxhighlight');
 
 module.exports = function (eleventyConfig) {
   eleventyConfig.addPlugin(syntaxHighlight);
-  eleventyConfig.addPassthroughCopy("docs-src/docs.css");
+  eleventyConfig.addPassthroughCopy('docs-src/docs.css');
-  eleventyConfig.addPassthroughCopy("docs-src/.nojekyll");
+  eleventyConfig.addPassthroughCopy('docs-src/.nojekyll');
+  eleventyConfig.addPassthroughCopy(
+    'node_modules/@webcomponents/webcomponentsjs'
+  );
+  eleventyConfig.addPassthroughCopy('node_modules/lit/polyfill-support.js');
   return {
     dir: {
       input: 'docs-src',

.eslintignore

@@ -0,0 +1,5 @@
+node_modules/*
+docs/*
+docs-src/*
+rollup-config.js
+custom-elements.json

.eslintrc.json

@@ -1,4 +1,5 @@
 {
+  "root": true,
   "extends": [
     "eslint:recommended",
     "plugin:@typescript-eslint/eslint-recommended",
@@ -10,17 +11,41 @@
     "sourceType": "module"
   },
   "plugins": ["@typescript-eslint"],
+  "env": {
+    "browser": true
+  },
   "rules": {
-    "no-unexpected-multiline": "off",
+    "no-prototype-builtins": "off",
-    "@typescript-eslint/indent": "off",
+    "@typescript-eslint/ban-types": "off",
     "@typescript-eslint/explicit-function-return-type": "off",
+    "@typescript-eslint/explicit-module-boundary-types": "off",
+    "@typescript-eslint/no-explicit-any": "error",
+    "@typescript-eslint/no-empty-function": "off",
     "@typescript-eslint/no-non-null-assertion": "off",
-    "@typescript-eslint/no-use-before-define": "off",
     "@typescript-eslint/no-unused-vars": [
       "warn",
       {
         "argsIgnorePattern": "^_"
       }
     ]
+  },
+  "overrides": [
+    {
+      "files": ["rollup.config.js", "web-test-runner.config.js"],
+      "env": {
+        "node": true
       }
+    },
+    {
+      "files": [
+        "*_test.ts",
+        "**/custom_typings/*.ts",
+        "packages/lit-ssr/src/test/integration/tests/**",
+        "packages/lit-ssr/src/lib/util/parse5-utils.ts"
+      ],
+      "rules": {
+        "@typescript-eslint/no-explicit-any": "off"
+      }
+    }
+  ]
 }

.gitignore

@@ -1,7 +1,7 @@
-/node_modules/
+node_modules/
 /lib/
 /test/
-
+custom-elements.json
 # top level source
 my-element.js
 my-element.js.map

.vscode/extensions.json

@@ -3,11 +3,7 @@
   // Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
 
   // List of extensions which should be recommended for users of this workspace.
-	"recommendations": [
+  "recommendations": ["runem.lit-plugin"],
-		"runem.lit-plugin"
-	],
   // List of extensions recommended by VS Code that should not be recommended for users of this workspace.
-	"unwantedRecommendations": [
+  "unwantedRecommendations": []
-
-	]
 }

LICENSE

@@ -1,18 +1,18 @@
 BSD 3-Clause License
 
-Copyright (c) 2019, The Polymer Authors. All rights reserved.
+Copyright (c) 2019 Google LLC. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
-* Redistributions of source code must retain the above copyright notice, this
+1. Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.
 
-* Redistributions in binary form must reproduce the above copyright notice,
+2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
 
-* Neither the name of the copyright holder nor the names of its
+3. Neither the name of the copyright holder nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.
 

README.md

@@ -30,7 +30,11 @@ Both the TypeScript compiler and lit-analyzer are configured to be very strict.
 
 ## Testing
 
-This sample uses Karma, Chai, Mocha, and the open-wc test helpers for testing. See the [open-wc testing documentation](https://open-wc.org/testing/testing.html) for more information.
+This sample modern-web.dev's
+[@web/test-runner](https://www.npmjs.com/package/@web/test-runner) along with
+Mocha, Chai, and some related helpers for testing. See the
+[modern-web.dev testing documentation](https://modern-web.dev/docs/test-runner/overview) for
+more information.
 
 Tests can be run with the `test` script:
 
@@ -40,7 +44,7 @@ npm test
 
 ## Dev Server
 
-This sample uses open-wc's [es-dev-server](https://github.com/open-wc/open-wc/tree/master/packages/es-dev-server) for previewing the project without additional build steps. ES dev server handles resolving Node-style "bare" import specifiers, which aren't supported in browsers. It also automatically transpiles JavaScript and adds polyfills to support older browsers.
+This sample uses modern-web.dev's [@web/dev-server](https://www.npmjs.com/package/@web/dev-server) for previewing the project without additional build steps. Web Dev Server handles resolving Node-style "bare" import specifiers, which aren't supported in browsers. It also automatically transpiles JavaScript and adds polyfills to support older browsers. See [modern-web.dev's Web Dev Server documentation](https://modern-web.dev/docs/dev-server/overview/) for more information.
 
 To run the dev server and open the project in a new browser tab:
 
@@ -53,15 +57,16 @@ There is a development HTML file located at `/dev/index.html` that you can view
 ## Editing
 
 If you use VS Code, we highly reccomend the [lit-plugin extension](https://marketplace.visualstudio.com/items?itemName=runem.lit-plugin), which enables some extremely useful features for lit-html templates:
-  - Syntax highlighting
-  - Type-checking
-  - Code completion
-  - Hover-over docs
-  - Jump to definition
-  - Linting
-  - Quick Fixes
 
-  The project is setup to reccomend lit-plugin to VS Code users if they don't already have it installed.
+- Syntax highlighting
+- Type-checking
+- Code completion
+- Hover-over docs
+- Jump to definition
+- Linting
+- Quick Fixes
+
+The project is setup to reccomend lit-plugin to VS Code users if they don't already have it installed.
 
 ## Linting
 

custom-elements.json

@@ -33,6 +33,24 @@
           "description": "The number of times the button has been clicked.",
           "type": "number",
           "default": "0"
+        },
+        {
+          "name": "renderRoot",
+          "description": "Node or ShadowRoot into which element DOM should be rendered. Defaults\nto an open shadowRoot.",
+          "type": "HTMLElement | ShadowRoot"
+        },
+        {
+          "name": "isUpdatePending",
+          "type": "boolean"
+        },
+        {
+          "name": "hasUpdated",
+          "type": "boolean"
+        },
+        {
+          "name": "updateComplete",
+          "description": "Returns a Promise that resolves when the element has completed updating.\nThe Promise value is a boolean that is `true` if the element completed the\nupdate without triggering another update. The Promise result is `false` if\na property was set inside `updated()`. If the Promise is rejected, an\nexception was thrown during the update.\n\nTo await additional asynchronous work, override the `getUpdateComplete`\nmethod. For example, it is sometimes useful to await a rendered element\nbefore fulfilling this Promise. To do this, first await\n`super.getUpdateComplete()`, then any subsequent state.",
+          "type": "Promise<boolean>"
         }
       ],
       "slots": [

dev/README.md

@@ -1,2 +1 @@
-
 This directory contains HTML files containing your element for development. By running `npm run build:watch` and `npm run serve` you can edit and see changes without bundling.

dev/index.html

@@ -1,9 +1,11 @@
-<!doctype html>
+<!DOCTYPE html>
 
 <html>
   <head>
-    <meta charset="utf-8">
+    <meta charset="utf-8" />
     <title>&lt;my-element> Demo</title>
+    <script src="../node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="../node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="../my-element.js"></script>
     <style>
       p {

docs-src/.eleventyignore

@@ -0,0 +1,2 @@
+# Ignore files with a leading underscore; useful for e.g. readmes in source documentation
+_*.md

docs-src/_data/api.11tydata.js

@@ -1,7 +1,15 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
 const fs = require('fs');
 
 module.exports = () => {
-  const customElements = JSON.parse(fs.readFileSync('custom-elements.json', 'utf-8'));
+  const customElements = JSON.parse(
+    fs.readFileSync('custom-elements.json', 'utf-8')
+  );
   return {
     customElements,
   };

docs-src/_includes/example.11ty.cjs

@@ -4,8 +4,7 @@ const relative = require('./relative-path.cjs');
 /**
  * This template extends the page template and adds an examples list.
  */
-module.exports = function(data) {
+module.exports = function (data) {
-
   return page({
     ...data,
     content: renderExample(data),
@@ -18,13 +17,22 @@ const renderExample = ({name, content, collections, page}) => {
     <section class="examples">
       <nav class="collection">
         <ul>
-          ${collections.example === undefined
+          ${
+            collections.example === undefined
               ? ''
-              : collections.example.map((post) => `
+              : collections.example
+                  .map(
+                    (post) => `
                   <li class=${post.url === page.url ? 'selected' : ''}>
-                    <a href="${relative(page.url, post.url)}">${post.data.description.replace('<', '&lt;')}</a>
+                    <a href="${relative(
+                      page.url,
+                      post.url
+                    )}">${post.data.description.replace('<', '&lt;')}</a>
                   </li>
-                `).join('')}
+                `
+                  )
+                  .join('')
+          }
         </ul>
       </nav>
       <div>

docs-src/_includes/footer.11ty.cjs

@@ -1,9 +1,9 @@
-module.exports = function(data) {
+module.exports = function (data) {
   return `
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>`;
 };

docs-src/_includes/header.11ty.cjs

@@ -1,4 +1,4 @@
-module.exports = function(data) {
+module.exports = function (data) {
   return `
 <header>
   <h1>&lt;my-element></h1>

docs-src/_includes/nav.11ty.cjs

@@ -1,6 +1,6 @@
 const relative = require('./relative-path.cjs');
 
-module.exports = function({page}) {
+module.exports = function ({page}) {
   return `
 <nav>
   <a href="${relative(page.url, '/')}">Home</a>

docs-src/_includes/page.11ty.cjs

@@ -3,7 +3,7 @@ const footer = require('./footer.11ty.cjs');
 const nav = require('./nav.11ty.cjs');
 const relative = require('./relative-path.cjs');
 
-module.exports = function(data) {
+module.exports = function (data) {
   const {title, page, content} = data;
   return `
 <!doctype html>
@@ -16,7 +16,12 @@ module.exports = function(data) {
     <link rel="stylesheet" href="${relative(page.url, '/docs.css')}">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="${relative(page.url, '/prism-okaidia.css')}" rel="stylesheet" />
-    <script type="module" src="${relative(page.url, '/my-element.bundled.js')}"></script>
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
+    <script type="module" src="${relative(
+      page.url,
+      '/my-element.bundled.js'
+    )}"></script>
   </head>
   <body>
     ${header()}

docs-src/api.11ty.cjs

@@ -15,7 +15,9 @@ module.exports = class Docs {
     const tags = customElements.tags;
     return `
       <h1>API</h1>
-      ${tags.map((tag) => `
+      ${tags
+        .map(
+          (tag) => `
         <h2>&lt;${tag.name}></h2>
         <div>
           ${tag.description}
@@ -23,41 +25,40 @@ module.exports = class Docs {
         ${renderTable(
           'Attributes',
           ['name', 'description', 'type', 'default'],
-          tag.attributes)}
+          tag.attributes
+        )}
         ${renderTable(
           'Properties',
           ['name', 'attribute', 'description', 'type', 'default'],
-          tag.properties)}  
+          tag.properties
-        ${/*
+        )}  
+        ${
+          /*
            * Methods are not output by web-component-analyzer yet (a bug), so
            * this is a placeholder so that at least _something_ will be output
            * when that is fixed, and element maintainers will hopefully have a
            * signal to update this file to add the neccessary columns.
            */
-          renderTable(
+          renderTable('Methods', ['name', 'description'], tag.methods)
-          'Methods',
+        }
-          ['name', 'description'],
+        ${renderTable('Events', ['name', 'description'], tag.events)}    
-          tag.methods)}
+        ${renderTable('Slots', ['name', 'description'], tag.slots)}  
-        ${renderTable(
-          'Events',
-          ['name', 'description'],
-          tag.events)}    
-        ${renderTable(
-          'Slots',
-          ['name', 'description'],
-          tag.slots)}  
         ${renderTable(
           'CSS Shadow Parts',
           ['name', 'description'],
-          tag.cssParts)}
+          tag.cssParts
+        )}
         ${renderTable(
           'CSS Custom Properties',
           ['name', 'description'],
-          tag.cssProperties)}
+          tag.cssProperties
-        `).join('')}
+        )}
+        `
+        )
+        .join('')}
     `;
   }
-}
+};
 
 /**
  * Renders a table of data, plucking the given properties from each item in
@@ -65,7 +66,7 @@ module.exports = class Docs {
  */
 const renderTable = (name, properties, data) => {
   if (data === undefined) {
-    return ''
+    return '';
   }
   return `
     <h3>${name}</h3>
@@ -73,13 +74,17 @@ const renderTable = (name, properties, data) => {
       <tr>
         ${properties.map((p) => `<th>${capitalize(p)}</th>`).join('')}
       </tr>
-      ${data.map((i) => `
+      ${data
+        .map(
+          (i) => `
         <tr>
           ${properties.map((p) => `<td>${i[p]}</td>`).join('')}
         </tr>
-      `).join('')}
-    </table>
       `
+        )
+        .join('')}
+    </table>
+  `;
 };
 
 const capitalize = (s) => s[0].toUpperCase() + s.substring(1);

docs-src/examples/index.md

@@ -19,10 +19,10 @@ description: A basic example
 <h3>CSS</h3>
 
 ```css
-  p {
+p {
   border: solid 1px blue;
   padding: 8px;
-  }
+}
 ```
 
 <h3>HTML</h3>

docs-src/index.md

@@ -55,12 +55,15 @@ title: <my-element> ⌲ Home
 ```js
 import {html, render} from 'lit-html';
 
-const name="lit-html";
+const name = 'lit-html';
 
-render(html`
+render(
+  html`
     <h2>This is a &lt;my-element&gt;</h2>
     <my-element .name=${name}></my-element>
-`, document.body);
+  `,
+  document.body
+);
 ```
 
   </div>

docs-src/install.md

@@ -20,11 +20,13 @@ npm CDNs like [unpkg.com]() can directly serve files that have been published to
 For this element to work from unpkg.com specifically, you need to include the `?module` query parameter, which tells unpkg.com to rewrite "bare" module specificers to full URLs.
 
 ### HTML
+
 ```html
 <script type="module" src="https://unpkg.com/my-element?module"></script>
 ```
 
 ### JavaScript
+
 ```html
 import {MyElement} from 'https://unpkg.com/my-element?module';
 ```

docs/_README/index.html

@@ -1,4 +0,0 @@
-<p>This directory containts the sources for the static site contained in the /docs/ directory. The site is based on the <a href="11ty.dev">eleventy</a> static site generator.</p>
-<p>The site is intended to be used with GitHub pages. To enable the site go to the GitHub settings and change the GitHub Pages &quot;Source&quot; setting to &quot;master branch /docs folder&quot;.</p>
-<p>To view the site locally, run <code>npm run docs:serve</code>.</p>
-<p>To edit the site, add to or edit the files in this directory then run <code>npm run docs</code> to build the site. The built files must be checked in and pushed to GitHub to appear on GitHub pages.</p>

docs/api/index.html

@@ -9,6 +9,8 @@
     <link rel="stylesheet" href="../docs.css">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="../prism-okaidia.css" rel="stylesheet" />
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="../my-element.bundled.js"></script>
   </head>
   <body>
@@ -65,6 +67,32 @@
           <td>count</td><td>count</td><td>The number of times the button has been clicked.</td><td>number</td><td>0</td>
         </tr>
       
+        <tr>
+          <td>renderRoot</td><td>undefined</td><td>Node or ShadowRoot into which element DOM should be rendered. Defaults
+to an open shadowRoot.</td><td>HTMLElement | ShadowRoot</td><td>undefined</td>
+        </tr>
+      
+        <tr>
+          <td>isUpdatePending</td><td>undefined</td><td>undefined</td><td>boolean</td><td>undefined</td>
+        </tr>
+      
+        <tr>
+          <td>hasUpdated</td><td>undefined</td><td>undefined</td><td>boolean</td><td>undefined</td>
+        </tr>
+      
+        <tr>
+          <td>updateComplete</td><td>undefined</td><td>Returns a Promise that resolves when the element has completed updating.
+The Promise value is a boolean that is `true` if the element completed the
+update without triggering another update. The Promise result is `false` if
+a property was set inside `updated()`. If the Promise is rejected, an
+exception was thrown during the update.
+
+To await additional asynchronous work, override the `getUpdateComplete`
+method. For example, it is sometimes useful to await a rendered element
+before fulfilling this Promise. To do this, first await
+`super.getUpdateComplete()`, then any subsequent state.</td><td>Promise<boolean></td><td>undefined</td>
+        </tr>
+      
     </table>
     
         
@@ -104,7 +132,7 @@
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>
   </body>

docs/examples/index.html

@@ -9,6 +9,8 @@
     <link rel="stylesheet" href="../docs.css">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="../prism-okaidia.css" rel="stylesheet" />
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="../my-element.bundled.js"></script>
   </head>
   <body>
@@ -32,14 +34,14 @@
       <nav class="collection">
         <ul>
           
-                  <li class=selected>
-                    <a href="">A basic example</a>
-                  </li>
-                
                   <li class=>
                     <a href="name-property/">Setting the name property</a>
                   </li>
                 
+                  <li class=selected>
+                    <a href="">A basic example</a>
+                  </li>
+                
         </ul>
       </nav>
       <div>
@@ -53,7 +55,7 @@
   <p>This is child content</p>
 </my-element>
 <h3>CSS</h3>
-<pre class="language-css"><code class="language-css">  <span class="token selector">p</span> <span class="token punctuation">{</span><br>    <span class="token property">border</span><span class="token punctuation">:</span> solid 1px blue<span class="token punctuation">;</span><br>    <span class="token property">padding</span><span class="token punctuation">:</span> 8px<span class="token punctuation">;</span><br>  <span class="token punctuation">}</span></code></pre>
+<pre class="language-css"><code class="language-css"><span class="token selector">p</span> <span class="token punctuation">{</span><br>  <span class="token property">border</span><span class="token punctuation">:</span> solid 1px blue<span class="token punctuation">;</span><br>  <span class="token property">padding</span><span class="token punctuation">:</span> 8px<span class="token punctuation">;</span><br><span class="token punctuation">}</span></code></pre>
 <h3>HTML</h3>
 <pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>my-element</span><span class="token punctuation">></span></span><br>  <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>p</span><span class="token punctuation">></span></span>This is child content<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>p</span><span class="token punctuation">></span></span><br><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>my-element</span><span class="token punctuation">></span></span></code></pre>
 
@@ -66,7 +68,7 @@
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>
   </body>

docs/examples/name-property/index.html

@@ -9,6 +9,8 @@
     <link rel="stylesheet" href="../../docs.css">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="../../prism-okaidia.css" rel="stylesheet" />
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="../../my-element.bundled.js"></script>
   </head>
   <body>
@@ -32,20 +34,20 @@
       <nav class="collection">
         <ul>
           
-                  <li class=>
-                    <a href="../">A basic example</a>
-                  </li>
-                
                   <li class=selected>
                     <a href="">Setting the name property</a>
                   </li>
                 
+                  <li class=>
+                    <a href="../">A basic example</a>
+                  </li>
+                
         </ul>
       </nav>
       <div>
         <p><my-element name="Earth"></my-element></p>
 <h3>HTML</h3>
-<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>my-element</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>Earth<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>my-element</span><span class="token punctuation">></span></span></code></pre>
+<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>my-element</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Earth<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>my-element</span><span class="token punctuation">></span></span></code></pre>
 
       </div>
     </section>
@@ -56,7 +58,7 @@
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>
   </body>

docs/index.html

@@ -9,6 +9,8 @@
     <link rel="stylesheet" href="docs.css">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="prism-okaidia.css" rel="stylesheet" />
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="my-element.bundled.js"></script>
   </head>
   <body>
@@ -42,7 +44,7 @@
 <section class="columns">
   <div>
 <p><code>&lt;my-element&gt;</code> can be configured with attributed in plain HTML.</p>
-<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>my-element</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>HTML<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>my-element</span><span class="token punctuation">></span></span></code></pre>
+<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>my-element</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>HTML<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>my-element</span><span class="token punctuation">></span></span></code></pre>
   </div>
   <div>
 <p><my-element name="HTML"></my-element></p>
@@ -52,7 +54,7 @@
 <section class="columns">
   <div>
 <p><code>&lt;my-element&gt;</code> can be used with declarative rendering libraries like Angular, React, Vue, and lit-html</p>
-<pre class="language-js"><code class="language-js"><span class="token keyword">import</span> <span class="token punctuation">{</span>html<span class="token punctuation">,</span> render<span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">'lit-html'</span><span class="token punctuation">;</span><br><br><span class="token keyword">const</span> name<span class="token operator">=</span><span class="token string">"lit-html"</span><span class="token punctuation">;</span><br><br><span class="token function">render</span><span class="token punctuation">(</span>html<span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string"><br>  &lt;h2>This is a &amp;lt;my-element&amp;gt;&lt;/h2><br>  &lt;my-element .name=</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>name<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">>&lt;/my-element><br></span><span class="token template-punctuation string">`</span></span><span class="token punctuation">,</span> document<span class="token punctuation">.</span>body<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
+<pre class="language-js"><code class="language-js"><span class="token keyword">import</span> <span class="token punctuation">{</span>html<span class="token punctuation">,</span> render<span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">'lit-html'</span><span class="token punctuation">;</span><br><br><span class="token keyword">const</span> name <span class="token operator">=</span> <span class="token string">'lit-html'</span><span class="token punctuation">;</span><br><br><span class="token function">render</span><span class="token punctuation">(</span><br>  html<span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string"><br>    &lt;h2>This is a &amp;lt;my-element&amp;gt;&lt;/h2><br>    &lt;my-element .name=</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>name<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">>&lt;/my-element><br>  </span><span class="token template-punctuation string">`</span></span><span class="token punctuation">,</span><br>  document<span class="token punctuation">.</span>body<br><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
   </div>
   <div>
 <h2>This is a &lt;my-element&gt;</h2>
@@ -66,7 +68,7 @@
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>
   </body>

docs/install/index.html

@@ -9,6 +9,8 @@
     <link rel="stylesheet" href="../docs.css">
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,400,600|Roboto+Mono">
     <link href="../prism-okaidia.css" rel="stylesheet" />
+    <script src="/node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
+    <script src="/node_modules/lit/polyfill-support.js"></script>
     <script type="module" src="../my-element.bundled.js"></script>
   </head>
   <body>
@@ -34,7 +36,7 @@
 <p>npm CDNs like <a href="">unpkg.com</a> can directly serve files that have been published to npm. This works great for standard JavaScript modules that the browser can load natively.</p>
 <p>For this element to work from unpkg.com specifically, you need to include the <code>?module</code> query parameter, which tells unpkg.com to rewrite &quot;bare&quot; module specificers to full URLs.</p>
 <h3>HTML</h3>
-<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>script</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>module<span class="token punctuation">"</span></span> <span class="token attr-name">src</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>https://unpkg.com/my-element?module<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token script"></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>script</span><span class="token punctuation">></span></span></code></pre>
+<pre class="language-html"><code class="language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>script</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>module<span class="token punctuation">"</span></span> <span class="token attr-name">src</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>https://unpkg.com/my-element?module<span class="token punctuation">"</span></span><span class="token punctuation">></span></span><span class="token script"></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>script</span><span class="token punctuation">></span></span></code></pre>
 <h3>JavaScript</h3>
 <pre class="language-html"><code class="language-html">import {MyElement} from 'https://unpkg.com/my-element?module';</code></pre>
 
@@ -44,7 +46,7 @@
 <footer>
   <p>
     Made with
-    <a href="https://github.com/PolymerLabs/lit-element-starter-ts">lit-element-starter-ts</a>
+    <a href="https://github.com/PolymerLabs/lit-starter-ts">lit-starter-ts</a>
   </p>
 </footer>
   </body>

docs/prism-okaidia.css

@@ -52,7 +52,7 @@ pre[class*="language-"] {
 .token.prolog,
 .token.doctype,
 .token.cdata {
-	color: slategray;
+	color: #8292a2;
 }
 
 .token.punctuation {

karma.conf.cjs

@@ -1,24 +0,0 @@
-const {createDefaultConfig} = require('@open-wc/testing-karma');
-const merge = require('deepmerge');
-
-module.exports = (config) => {
-  config.set(
-    merge(createDefaultConfig(config), {
-      frameworks: ['mocha', 'chai'],
-      client: {
-        mocha: {ui: 'tdd'},
-      },
-      files: [
-        {
-          pattern: config.grep ? config.grep : 'test/**/*_test.js',
-          type: 'module',
-        },
-      ],
-      // See the karma-esm docs for all options
-      esm: {
-        nodeResolve: true,
-      },
-    })
-  );
-  return config;
-};

package.json

@@ -1,5 +1,6 @@
 {
-  "name": "lit-element-starter-ts",
+  "name": "@lit/lit-starter-ts",
+  "private": true,
   "version": "0.0.0",
   "description": "A simple web component",
   "main": "my-element.js",
@@ -12,57 +13,58 @@
     "lint": "npm run lint:lit-analyzer && npm run lint:eslint",
     "lint:eslint": "eslint 'src/**/*.ts'",
     "lint:lit-analyzer": "lit-analyzer",
-    "format": "prettier src/* --write",
+    "format": "prettier \"**/*.{cjs,html,js,json,md,ts}\" --ignore-path ./.eslintignore --write",
     "docs": "npm run docs:clean && npm run build && npm run analyze && npm run docs:build && npm run docs:assets && npm run docs:gen",
     "docs:clean": "rimraf docs",
     "docs:gen": "eleventy --config=.eleventy.cjs",
     "docs:gen:watch": "eleventy --config=.eleventy.cjs --watch",
     "docs:build": "rollup -c --file docs/my-element.bundled.js",
     "docs:assets": "cp node_modules/prismjs/themes/prism-okaidia.css docs/",
-    "docs:serve": "es-dev-server --root-dir=docs --node-resolve --watch",
+    "docs:serve": "wds --root-dir=docs --node-resolve --watch",
     "analyze": "wca analyze \"src/**/*.ts\" --outFile custom-elements.json",
-    "serve": "es-dev-server --node-resolve --watch",
+    "serve": "wds --watch",
-    "test": "karma start karma.conf.cjs",
+    "test": "wtr",
-    "test:watch": "karma start karma.conf.cjs --auto-watch=true --single-run=false",
+    "test:watch": "npm run test -- --watch",
-    "test:update-snapshots": "karma start karma.conf.cjs --update-snapshots",
-    "test:prune-snapshots": "karma start karma.conf.cjs --prune-snapshots",
     "checksize": "rollup -c ; cat my-element.bundled.js | gzip -9 | wc -c ; rm my-element.bundled.js"
   },
   "keywords": [
     "web-components",
     "lit-element",
-    "typescript"
+    "typescript",
+    "lit"
   ],
-  "author": "The Polymer Authors",
+  "author": "Google LLC",
   "license": "BSD-3-Clause",
   "dependencies": {
-    "lit-element": "^2.3.1"
+    "lit": "^2.0.0-rc.1"
   },
   "devDependencies": {
-    "@11ty/eleventy": "^0.10.0",
+    "@11ty/eleventy": "^0.12.1",
     "@11ty/eleventy-plugin-syntaxhighlight": "^3.0.1",
-    "@open-wc/testing": "^2.5.10",
+    "@esm-bundle/chai": "^4.1.5",
-    "@open-wc/testing-karma": "^3.3.11",
+    "@open-wc/testing": "^2.5.32",
-    "@rollup/plugin-replace": "^2.3.1",
+    "@open-wc/testing-karma": "^4.0.9",
-    "@types/chai": "^4.2.11",
+    "@rollup/plugin-node-resolve": "^9.0.0",
+    "@rollup/plugin-replace": "^2.3.3",
     "@types/mocha": "^7.0.2",
     "@typescript-eslint/eslint-plugin": "^2.27.0",
     "@typescript-eslint/parser": "^2.27.0",
-    "chai": "^4.2.0",
+    "@web/dev-server": "0.0.29",
+    "@web/dev-server-legacy": "^0.1.4",
+    "@web/dev-server-rollup": "^0.2.7",
+    "@web/test-runner": "^0.12.15",
+    "@web/test-runner-mocha": "^0.3.5",
+    "@web/test-runner-playwright": "^0.8.4",
+    "@webcomponents/webcomponentsjs": "^2.5.0",
     "deepmerge": "^4.2.2",
-    "es-dev-server": "^1.46.1",
     "eslint": "^6.8.0",
-    "karma": "^4.4.1",
-    "karma-chai": "^0.1.0",
-    "karma-mocha": "^1.3.0",
     "lit-analyzer": "^1.1.10",
     "mocha": "^7.1.1",
     "prettier": "^2.0.4",
     "rimraf": "^3.0.2",
-    "rollup": "^1.32.1",
+    "rollup": "^2.28.2",
-    "rollup-plugin-filesize": "^7.0.0",
+    "rollup-plugin-summary": "^1.2.3",
-    "rollup-plugin-node-resolve": "^5.2.0",
+    "rollup-plugin-terser": "^7.0.2",
-    "rollup-plugin-terser": "^5.3.0",
     "typescript": "^3.8.3",
     "web-component-analyzer": "^1.0.3"
   }

rollup.config.js

@@ -1,20 +1,12 @@
 /**
  * @license
- * Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+ * Copyright 2018 Google LLC
- * This code may only be used under the BSD style license found at
+ * SPDX-License-Identifier: BSD-3-Clause
- * http://polymer.github.io/LICENSE.txt
- * The complete set of authors may be found at
- * http://polymer.github.io/AUTHORS.txt
- * The complete set of contributors may be found at
- * http://polymer.github.io/CONTRIBUTORS.txt
- * Code distributed by Google as part of the polymer project is also
- * subject to an additional IP rights grant found at
- * http://polymer.github.io/PATENTS.txt
  */
 
-import filesize from 'rollup-plugin-filesize';
+import summary from 'rollup-plugin-summary';
 import {terser} from 'rollup-plugin-terser';
-import resolve from 'rollup-plugin-node-resolve';
+import resolve from '@rollup/plugin-node-resolve';
 import replace from '@rollup/plugin-replace';
 
 export default {
@@ -32,6 +24,7 @@ export default {
     replace({'Reflect.decorate': 'undefined'}),
     resolve(),
     terser({
+      ecma: 2017,
       module: true,
       warnings: true,
       mangle: {
@@ -40,8 +33,6 @@ export default {
         },
       },
     }),
-    filesize({
+    summary(),
-      showBrotliSize: true,
-    }),
   ],
 };

src/my-element.ts

@@ -1,18 +1,11 @@
 /**
  * @license
- * Copyright (c) 2019 The Polymer Project Authors. All rights reserved.
+ * Copyright 2019 Google LLC
- * This code may only be used under the BSD style license found at
+ * SPDX-License-Identifier: BSD-3-Clause
- * http://polymer.github.io/LICENSE.txt
- * The complete set of authors may be found at
- * http://polymer.github.io/AUTHORS.txt
- * The complete set of contributors may be found at
- * http://polymer.github.io/CONTRIBUTORS.txt
- * Code distributed by Google as part of the polymer project is also
- * subject to an additional IP rights grant found at
- * http://polymer.github.io/PATENTS.txt
  */
 
-import {LitElement, html, customElement, property, css} from 'lit-element';
+import {LitElement, html, css} from 'lit';
+import {customElement, property} from 'lit/decorators.js';
 
 /**
  * An example element.

src/test/my-element_test.ts

@@ -1,4 +1,11 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
 import {MyElement} from '../my-element.js';
+
 import {fixture, html} from '@open-wc/testing';
 
 const assert = chai.assert;
@@ -47,4 +54,10 @@ suite('my-element', () => {
     `
     );
   });
+
+  test('styling applied', async () => {
+    const el = (await fixture(html`<my-element></my-element>`)) as MyElement;
+    await el.updateComplete;
+    assert.equal(getComputedStyle(el).paddingTop, '16px');
+  });
 });

tsconfig.json

@@ -1,11 +1,12 @@
 {
   "compilerOptions": {
-    "target": "es2017",
+    "target": "es2019",
-    "module": "es2015",
+    "module": "es2020",
-    "lib": ["es2017", "dom", "dom.iterable"],
+    "lib": ["es2020", "DOM", "DOM.Iterable"],
     "declaration": true,
     "declarationMap": true,
     "sourceMap": true,
+    "inlineSources": true,
     "outDir": "./",
     "rootDir": "./src",
     "strict": true,
@@ -13,6 +14,8 @@
     "noUnusedParameters": true,
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
     "moduleResolution": "node",
     "allowSyntheticDefaultImports": true,
     "experimentalDecorators": true,

web-dev-server.config.js

@@ -0,0 +1,20 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+import {legacyPlugin} from '@web/dev-server-legacy';
+
+export default {
+  nodeResolve: true,
+  preserveSymlinks: true,
+  plugins: [
+    legacyPlugin({
+      polyfills: {
+        // Manually imported in index.html file
+        webcomponents: false,
+      },
+    }),
+  ],
+};

web-test-runner.config.js

@@ -0,0 +1,119 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+import {legacyPlugin} from '@web/dev-server-legacy';
+import {playwrightLauncher} from '@web/test-runner-playwright';
+
+// Uncomment for testing on Sauce Labs
+// Must run `npm i --save-dev @web/test-runner-saucelabs` and set
+// SAUCE_USERNAME and SAUCE_USERNAME environment variables
+// ===========
+// import {createSauceLabsLauncher} from '@web/test-runner-saucelabs';
+// const sauceLabsLauncher = createSauceLabsLauncher(
+//   {
+//     user: process.env.SAUCE_USERNAME,
+//     key: process.env.SAUCE_USERNAME,
+//   },
+//   {
+//     'sauce:options': {
+//       name: 'unit tests',
+//       build: `${process.env.GITHUB_REF ?? 'local'} build ${
+//         process.env.GITHUB_RUN_NUMBER ?? ''
+//       }`,
+//     },
+//   }
+// );
+
+// Uncomment for testing on BrowserStack
+// Must run `npm i --save-dev @web/test-runner-browserstack` and set
+// BROWSER_STACK_USERNAME and BROWSER_STACK_ACCESS_KEY environment variables
+// ===========
+// import {browserstackLauncher as createBrowserstackLauncher} from '@web/test-runner-browserstack';
+// const browserstackLauncher = (config) => createBrowserstackLauncher({
+//   capabilities: {
+//     'browserstack.user': process.env.BROWSER_STACK_USERNAME,
+//     'browserstack.key': process.env.BROWSER_STACK_ACCESS_KEY,
+//     project: 'my-element',
+//     name: 'unit tests',
+//     build: `${process.env.GITHUB_REF ?? 'local'} build ${
+//       process.env.GITHUB_RUN_NUMBER ?? ''
+//     }`,
+//     ...config,
+//   }
+// });
+
+const browsers = {
+  // Local browser testing via playwright
+  // ===========
+  chromium: playwrightLauncher({product: 'chromium'}),
+  firefox: playwrightLauncher({product: 'firefox'}),
+  webkit: playwrightLauncher({product: 'webkit'}),
+
+  // Uncomment example launchers for running on Sauce Labs
+  // ===========
+  // chromium: sauceLabsLauncher({browserName: 'chrome', browserVersion: 'latest', platformName: 'Windows 10'}),
+  // firefox: sauceLabsLauncher({browserName: 'firefox', browserVersion: 'latest', platformName: 'Windows 10'}),
+  // edge: sauceLabsLauncher({browserName: 'MicrosoftEdge', browserVersion: 'latest', platformName: 'Windows 10'}),
+  // ie11: sauceLabsLauncher({browserName: 'internet explorer', browserVersion: '11.0', platformName: 'Windows 10'}),
+  // safari: sauceLabsLauncher({browserName: 'safari', browserVersion: 'latest', platformName: 'macOS 10.15'}),
+
+  // Uncomment example launchers for running on Sauce Labs
+  // ===========
+  // chromium: browserstackLauncher({browserName: 'Chrome', os: 'Windows', os_version: '10'}),
+  // firefox: browserstackLauncher({browserName: 'Firefox', os: 'Windows', os_version: '10'}),
+  // edge: browserstackLauncher({browserName: 'MicrosoftEdge', os: 'Windows', os_version: '10'}),
+  // ie11: browserstackLauncher({browserName: 'IE', browser_version: '11.0', os: 'Windows', os_version: '10'}),
+  // safari: browserstackLauncher({browserName: 'Safari', browser_version: '14.0', os: 'OS X', os_version: 'Big Sur'}),
+};
+
+// Prepend BROWSERS=x,y to `npm run test` to run a subset of browsers
+// e.g. `BROWSERS=chromium,firefox npm run test`
+const noBrowser = (b) => {
+  throw new Error(`No browser configured named '${b}'; using defaults`);
+};
+let commandLineBrowsers;
+try {
+  commandLineBrowsers = process.env.BROWSERS?.split(',').map(
+    (b) => browsers[b] ?? noBrowser(b)
+  );
+} catch (e) {
+  console.warn(e);
+}
+
+// https://modern-web.dev/docs/test-runner/cli-and-configuration/
+export default {
+  rootDir: '.',
+  files: ['./test/**/*_test.js'],
+  nodeResolve: true,
+  preserveSymlinks: true,
+  browsers: commandLineBrowsers ?? Object.values(browsers),
+  testFramework: {
+    // https://mochajs.org/api/mocha
+    config: {
+      ui: 'tdd',
+    },
+  },
+  plugins: [
+    // Detect browsers without modules (e.g. IE11) and transform to SystemJS
+    // (https://modern-web.dev/docs/dev-server/plugins/legacy/).
+    legacyPlugin({
+      polyfills: {
+        webcomponents: true,
+        // Inject lit's polyfill-support module into test files, which is required
+        // for interfacing with the webcomponents polyfills
+        custom: [
+          {
+            name: 'lit-polyfill-support',
+            path: 'node_modules/lit/polyfill-support.js',
+            test:
+              "!('attachShadow' in Element.prototype) || !('getRootNode' in Element.prototype) || window.ShadyDOM && window.ShadyDOM.force",
+            module: false,
+          },
+        ],
+      },
+    }),
+  ],
+};