Prepare 2.5.0 release

.github/ISSUE_TEMPLATE.md

@@ -1,10 +1,9 @@
 <!--
 If you are asking a question rather than filing a bug, try one of these instead:
-- StackOverflow (https://stackoverflow.com/questions/tagged/polymer)
-- Polymer Slack Channel (https://bit.ly/polymerslack)
-- Mailing List (https://groups.google.com/forum/#!forum/polymer-dev)
+- StackOverflow (https://stackoverflow.com/questions/tagged/lit-element)
+- Lit and Friends Slack Channel (https://lit.dev/slack-invite/)
 -->
-<!-- Instructions For Filing a Bug: https://github.com/Polymer/lit-element/blob/master/CONTRIBUTING.md#filing-bugs -->
+<!-- Instructions For Filing a Bug: https://github.com/lit/lit-element/blob/master/CONTRIBUTING.md#filing-bugs -->
 ### Description
 <!-- Example: Error thrown when calling `appendChild` on Lit element -->
 
@@ -45,5 +44,5 @@ Example:
 <!--
 `npm ls` will show the version of webcomponents.js and lit-element
 -->
-- lit-element: vX.X.X
+- lit-element: v2.X.X
 - webcomponents: vX.X.X

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,3 +1,3 @@
-<!-- Instructions: https://github.com/Polymer/lit-element/blob/master/CONTRIBUTING.md#contributing-pull-requests -->
+<!-- Instructions: https://github.com/lit/lit-element/blob/master/CONTRIBUTING.md#contributing-pull-requests -->
 ### Reference Issue
 <!-- Example: Fixes #1234 -->

.gitignore

@@ -9,6 +9,11 @@
 /lit-element.d.ts
 /lit-element.d.ts.map
 
+/decorators.js
+/decorators.js.map
+/decorators.d.ts
+/decorators.d.ts.map
+
 /test/**/*.d.ts
 /test/**/*.d.ts.map
 /test/**/*.js

CHANGELOG.md

@@ -17,7 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 <!-- ### Removed -->
 <!-- ### Fixed -->
 
-## Unreleased
+## [2.5.0] - 2021-04-29
 
 ### Changed
 

CONTRIBUTING.md

@@ -1,27 +1,20 @@
-# Contributing to Polymer
+# Contributing to LitElement
 
-There are many ways to contribute to the Polymer project! We welcome and truly appreciate contribution in all forms - issues and pull requests to the [main library](https://github.com/polymer/polymer), issues and pull requests to the [elements the Polymer team maintains](https://github.com/polymerelements), issues and pull requests to one of our many [Polymer-related tools](https://github.com/polymer), and of course we love to hear about any Polymer elements that you build to share with the community!
+There are many ways to contribute to Lit! We welcome and truly appreciate contribution in all forms - issues and pull requests to the [main libraries](https://github.com/lit/lit), issues and pull requests to the [lit.dev site](https://github.com/lit/lit.dev), and of course we love to hear about any Lit components that you build to share with the community!
+
+## Status of this repository
+
+The main LitElement code has been moved into the [Lit monorepo](https://github.com/lit/lit). All new development is happening there. This repository is only for critical updates to `lit-element` 2.x.
 
 ## Logistics
 
-### Communicating with the Polymer team
+### Communicating with the team
 
 Beyond GitHub, we try to have a variety of different lines of communication open:
 
-* [Blog](https://blog.polymer-project.org/)
+* [Blog](https://lit.dev/blog/)
 * [Twitter](https://twitter.com/buildWithLit)
-* [Mailing list](https://groups.google.com/forum/#!forum/polymer-dev)
-* [Slack channel](https://bit.ly/polymerslack)
-
-### The Polymer Repositories
-
-Because of the component-based nature of the Polymer project, we tend to have lots of different repositories. Our main repository for the Polymer library itself is at [github.com/Polymer/polymer](https://github.com/polymer/polymer). File any issues or pull requests that have to do with the core library on that repository, and we'll take a look ASAP.
-
-We keep all of the element "product lines" that the Polymer team maintains and distributes in the [PolymerElements](https://github.com/polymerelements) organization. For any element-specific issues or pull requests, file directly on the element's repository, such as the `paper-button` repository at [github.com/polymerelements/paper-button](https://github.com/polymerelements/paper-button). Of course, the elements built by the Polymer team are just a tiny fraction of all the Polymer-based elements out there - catalogs of other web components include [https://www.webcomponents.org/](https://github.com/webcomponents/webcomponents.org) and [component.kitchen](https://component.kitchen).
-
-The GoogleWebComponents element product line is maintained by teams all across Google, and so is kept in a separate organization: the [GoogleWebComponents](https://github.com/googlewebcomponents) org. Feel free to file issues and PR's on those elements directly in that organization.
-
-We also track each element product line overall in "meta-repos", named as `$PRODUCTLINE-elements`. These include [paper-elements](https://github.com/polymerelements/paper-elements), [iron-elements](https://github.com/polymerelements/iron-elements), [gold-elements](https://github.com/polymerelements/gold-elements), and more. Feel free to file issues for element requests on those meta-repos, and the README in each repo tracks a roadmap for the product line.
+* [Slack channel](https://lit.dev/slack-invite/)
 
 ### Contributor License Agreement
 
@@ -39,11 +32,9 @@ Docs source is in the `docs` folder. To build the site yourself, see the instruc
 
 ### Filing bugs
 
-The Polymer team heavily uses (and loves!) GitHub for all of our software management. We use GitHub issues to track all bugs and features.
+The Lit team heavily uses (and loves!) GitHub for all of our software management. We use GitHub issues to track all bugs and features.
 
-If you find an issue, please do file it on the repository. The [lit-element issues](https://github.com/Polymer/lit-element/issues) should be used only for issues on the lit-element library itself - bugs somewhere in the core codebase.
-
-For issues with elements the team maintains, please file directly on the element's repository. If you're not sure if a bug stems from the element or the library, air toward filing it on the element and we'll move the issue if necessary.
+If you find an issue, please do file it on the repository. The [lit-element issues](https://github.com/lit/lit-element/issues) should be used only for issues on the lit-element library itself - bugs somewhere in the core codebase.
 
 Please file issues using the issue template provided, filling out as many fields as possible. We love examples for addressing issues - issues with a jsBin, Plunkr, jsFiddle, or glitch.me repro will be much easier for us to work on quickly. You can start with [this StackBlitz](https://stackblitz.com/edit/lit-element-example?file=index.js) which sets up the basics to demonstrate a lit-element.  If you need your repro to run in IE11, you can start from [this glitch](https://glitch.com/edit/#!/hello-lit-element?path=index.html:1:0), which serves the source via polyserve for automatic transpilation, although you must sign up for a glitch.me account to ensure your code persists for more than 5 days (note the glitch.me _editing environment_ is not compatible with IE11, however the "live" view link of the running code should work).
 
@@ -64,31 +55,19 @@ PR's are even better than issues. We gladly accept community pull requests. In g
 
 If you've completed all of these steps the core team will do its best to respond to the PR as soon as possible.
 
-#### Contributing Code to Elements
-
-Though the aim of the Polymer library is to allow lots of flexibility and not get in your way, we work to standardize our elements to make them as toolable and easy to maintain as possible.
-
-All elements should follow the [Polymer element style guide](https://www.polymer-project.org/3.0/docs/tools/documentation), which defines how to specify properties, documentation, and more. It's a great guide to follow when building your own elements as well, for maximum standardization and toolability. For instance, structuring elements following the style guide will ensure that they work with the [`iron-component-page`](https://github.com/polymerelements/iron-component-page) element, an incredibly easy way to turn any raw element directly into a documentation page.
-
-#### Contributing Code to the Polymer library
+#### Contributing Code to LitElement
 
 We follow the most common JavaScript and HTML style guidelines for how we structure our code - in general, look at the code and you'll know how to contribute! If you'd like a bit more structure, the [Google JavaScript Styleguide](https://google.github.io/styleguide/javascriptguide.xml) is a good place to start.
 
-Polymer also participates in Google's [Patch Rewards Program](https://www.google.com/about/appsecurity/patch-rewards/), where you can earn cold, hard cash for qualifying security patches to the Polymer library. Visit the [patch rewards page](https://www.google.com/about/appsecurity/patch-rewards/) to find out more.
+Lit also participates in Google's [Patch Rewards Program](https://www.google.com/about/appsecurity/patch-rewards/), where you can earn cold, hard cash for qualifying security patches to the Lit library. Visit the [patch rewards page](https://www.google.com/about/appsecurity/patch-rewards/) to find out more.
 
 ## Unit tests
 
-All Polymer projects use [`polymer-cli`](https://github.com/Polymer/tools/tree/master/packages/cli) for unit tests.
-
-For maximum flexibility, install `polymer-cli` locally:
-
-    npm install -g polymer-cli
-
 ### Running the lit-element unit tests
 
 To run the lit-element unit tests:
 
-1.  Clone the [lit-element repo](https://github.com/polymer/lit-element).
+1.  Clone the [lit-element repo](https://github.com/lit/lit-element).
 
 2.  Install the dependencies:
 
@@ -98,45 +77,13 @@ To run the lit-element unit tests:
 
 		npm test
 
-    Or if you have `polymer-cli` installed locally:
-
-		polymer test --npm
-
 To run individual test suites:
 
 <code>npm test <var>path/to/suite</var></code>
 
-Or:
-
-<code>polymer test --npm <var>path/to/suite</var></code>
-
-For example:
-
-	polymer test --npm test/index.html
-
-You can also run tests in the browser:
-
-	polymer serve --npm
-
-Navigate to:
-
-[`http://localhost:8080/components/@polymer/lit-element/test/index.html`](http://localhost:8080/components/@polymer/lit-element/test/index.html)
 
 ### Configuring `web-component-tester`
 
-By default, `polymer test` runs tests on all installed browsers. You can configure it
-to run tests on a subset of available browsers, or to run tests remotely using Sauce Labs.
-
-See the [`web-component-tester` README](https://github.com/Polymer/tools/tree/master/packages/web-component-tester) for
-information on configuring the tool using by `polymer-cli` to run the tests.
-
-### Viewing the source documentation locally
-
-You can view the updates you make to the source documentation locally with the following steps.
-Make sure to rerun step 1 after every change you make.
-
-1. Run `polymer analyze > analysis.json`
-
-1. Run `polymer serve`
+By default, `npm test` runs tests on all installed browsers. You can configure it to run tests on a subset of available browsers, or to run tests remotely using Sauce Labs.
 
-1. Open `http://127.0.0.1:PORT/components/polymer/` to view the documentation
+See the [`web-component-tester` README](https://github.com/Polymer/tools/tree/master/packages/web-component-tester) for information on configuring the test runner.

README.md

@@ -2,15 +2,14 @@
 
 LitElement is simple base class for creating fast, lightweight web components with [lit-html](https://lit-html.polymer-project.org/).
 
-[![Build Status](https://travis-ci.org/Polymer/lit-element.svg?branch=master)](https://travis-ci.org/Polymer/lit-element)
+[![Build Status](https://travis-ci.org/lit/lit-element.svg?branch=master)](https://travis-ci.org/lit/lit-element)
 [![Published on npm](https://img.shields.io/npm/v/lit-element.svg)](https://www.npmjs.com/package/lit-element)
 [![Join our Slack](https://img.shields.io/badge/slack-join%20chat-4a154b.svg)](https://lit.dev/slack-invite/)
-[![Mentioned in Awesome lit-html](https://awesome.re/mentioned-badge.svg)](https://github.com/web-padawan/awesome-lit-html)
+[![Mentioned in Awesome lit-html](https://awesome.re/mentioned-badge.svg)](https://github.com/web-padawan/awesome-lit)
 
 ## Looking for Lit?
 
-LitElement is now part of the [Lit library monorepo](https://github.com/lit/lit). 
-Lit 2 includes lit-html 2.x and LitElement 3.x. 
+LitElement is now part of the [Lit library monorepo](https://github.com/lit/lit). Lit 2 includes lit-html 2.x and LitElement 3.x. 
 
 This repo contains the code for LitElement 2.x.
 
@@ -98,10 +97,11 @@ To prepare for Lit 2, update these APIs:
 
 | LitElement 2.4         | LitElement 2.5/Lit 2  |
 |------------------------|-----------------------|
-| `import {customElement} from 'lit-element';` | `import {customElement} from 'lit-element/decorators.js';`
+| Decorator imports:<br>`import {customElement} from 'lit-element';` | `import {customElement} from 'lit-element/decorators.js';`
 | `@internalProperty() foo;`  | `@state() foo;`            |
 | Override `_getUpdateComplete()` | Override `getUpdateComplete()` |
-
+| Shadow root options:</br> Override `createRenderRoot()`. | Add `static shadowRootOptions`.
+| `import {UpdatingElement} from 'lit-element';` |  `import {ReactiveElement} from 'lit-element';`  |
 ## Contributing
 
 Please see [CONTRIBUTING.md](./CONTRIBUTING.md).