New Features

• Added LegacyDataMixin to optionally use Polymer v1's behavior in handling of undefined in data bindings.
  • Intended to help larger apps transition from Polymer v1 to v3.
• Implement opt-in strictTemplatePolicy to protect against XSS attacks with templating
  • Enabling strictTemplatePolicy by calling setStrictTemplatePolicy(true) setting causes the following changes in behavior:
    • All "self-stamping" templates including <dom-bind>, <dom-repeat>, and <dom-if> will throw errors and not stamp if not originating from inside the template of a trusted element registered via script.
    • Template retrieval from <dom-module> is disabled (since templates should be defined inline in JS via static get template() using the html tag function).
    • Legacy <dom-module> template lookup can be re-enabled via setAllowTemplateFromDomModule(true) setting; under that setting, the following additional behavior will apply:
      • Re-registration of <dom-module> will throw and cause template lookup for that element name to return null.
      • Elements that do not have templates by design must explicitly indicate a null template to prevent template retrieval from inject <dom-module>s, otherwise they will throw an error

Meaningful Changes

• A LOT of typing improvements for both Typescript and Closure compiler
• Add back ability to set window.Polymer.sanitizeDOMValue before Polymer loads
• Fix data-binding notification events when the bound element has children.
• Make sure static get properties() is only read once.

Raw Notes

• update dependencies (commit)

• Add beforeRegister callback to externs (commit)

• Make toggleAttribute match with native signature (#5372) (commit)

• Fixed typos on lines 133 and 157 (#5409) (commit)

• Fix signature of toggleAttribute to match native version (#5370) (commit)

• Update jsdoc for PropertyEffects.splice (#5367) (commit)

• Expand type of LegacyElementMixin#listen and unlisten to accept EventTargets. (commit)

• Update gen-closure-declarations to 0.5.0 (#5360) (commit)

• Add TypeScript types for observer parameters. (#5359) (commit)

• Add missing return type to attributeChanged (commit)

• Add specific type for behaviors (commit)

• Improve typings for legacy elements (commit)

• Add @export (commit)

• Improve types of flattened-nodes-observer further. (commit)

• Add cast for compilation (commit)

• Only generate types once on Travis (commit)

• Move type generation from prepack to prepare (commit)

• Collapse imports for file into one statement (commit)

• Cleanup modulizer conversion leftovers (#5347) (commit)

• Add comments re: need for mixing in before metaprogramming (commit)

• regen-package-lock (commit)

• Don't run Firefox in headless mode. (commit)

• Fix jsdoc syntax. (commit)

• Updates based on code review. Add computed tests. (commit)

• Use type generator binary instead of gulp script. (commit)

• Remove unnecessary @const. (commit)

• Add return description. (commit)

• Grandfather defaulting sanitizeDOMValue from legacy Polymer object. (commit)

• Minor changes to formatting and jsdoc (commit)

• Update paths in gulpfile (commit)

• Fix mixin jsdoc. (commit)

• Add legacy-data-mixin as 1.x->2.x/3.x migration aide. Fixes #5262. (commit)

• Fix jsdoc to pass lint (commit)

• Add documentation to boot.js (commit)

• The return type of mixinBehaviors is unknown (commit)

• Export EventApi, same as DomApi (commit)

• Remove undocumented logging feature (#5331) (commit)

• Cleanup element-mixin leftovers from modulizer (commit)

• Use case-map lib in a saner way. (commit)

• Fix a grab bag of closure compiler warnings. (commit)

• Protect DomModule.import against renaming (commit)

• Add @nocollapse for jscompiler (commit)

• Ensure boot.js can only be parsed as a module (commit)

• Use simpler class declaration and export form (#5325) (commit)

• Ensure unresolved.js is an es module (#5324) (commit)

• Move version to ElementMixin prototype (commit)

• Use relative path module specifier in gen-tsd autoImport setting. (commit)

• Update TemplateStamp event listen param types from Node to EventTarget. (#5320) (commit)

• Add test for direct assignment to template. (commit)

• Add a template setter to ElementMixin. (commit)

• Export the current Polymer version in polymer-element.js (commit)

• Make Polymer gestures library safe for Closure property renaming (take 2). (#5314) (commit)

• Make event notification handler read the value from currentTarget, (#5313) (commit)

• [ci skip] update changelog (commit)

• Upstream externs changes for DomRepeatEvent (commit)

• Back to single template getter. Add more comments. (commit)

• Revert to legacy template getter, update tests. (commit)

• More updates based on code review. (commit)

• Fix allowTemplateFromDomModule opt-in (commit)

• Fix lint warnings. (commit)

• Updates based on code review. (commit)

• npm upgrade dependencies (commit)

• Fix lint warnings. (commit)

• Catch errors on top window using uncaughtErrorFilter Works around safari quirk when running in iframe (commit)

• Fix latent (benign) error thrown when removing dom-if via innerHTML. (commit)

• Use setting via setStrictTemplatePolicy export. (commit)

• Add tests. (commit)

• Implement opt-in strictTemplatePolicy (flag TBD) - disable dom-bind - disable dom-module template lookup - disable templatizer of templates not stamped in trusted polymer template (commit)

• Ensure properties is only called once (commit)

• Remove dom-module in test (commit)

Meaningful Changes

• Fix taps on elements with disabled property
• closure compiler fixups
• Allow legacy element property definitions with only a type.
• Replace an attempt to spread a NodeList to an array with Array.from for Safari 9, where NodeList is not iterable.
• Ignore shady CSS scoping in getComposedHTML
• Make event notification handler read the value from currentTarget

Raw Notes

• Make event notification handler read the value from currentTarget, (#5309) (commit)

• Regenerate types. (commit)

• Annotate another two ephemeral classes. (commit)

• Mark some ephemeral super classes as private. (commit)

• Annotate Node parameter as not null. (commit)

• Updates for improved type generation. (commit)

• Disable combined CE+SD polyfill testing on browsers with native support, for test economy. (commit)

• Extend Safari exceptions beyond 10.1 (commit)

• Extend Edge exceptions beyond Edge 16 (commit)

• Ignore shady CSS scoping in getComposedHTML (commit)

• Update gen-typescript-declarations and generate constructor types (#5281) (commit)

• split chrome and firefox runs, maybe fewer timeouts for firefox (commit)

• port other fixes as well (commit)

• Port Closure Compiler fixes to polymer-externs (commit)

• Fix method to force CE polyfill on. Fixes #5267. (commit)

• Fix lint errors. (commit)

• Add a test for touches on labels causing clicks on the labelled element. (commit)

• Replace an attempt to spread a NodeList to an array with Array.from for Safari 9, where NodeList is not iterable. (commit)

• IE fixes (commit)

• Use node 8 (commit)

• Only disable tabs for "disablable" elements (commit)

• Add @const to elements (commit)

• Add user-importable files to bower.json's main field for modulizer. (commit)

• Add reasoning for suppress missingProperties (commit)

• Don't rely on dom-module synchronously until WCR. (commit)

• Avoid closure warnings. (commit)

• Add ability to define importMeta on legacy elements. Fixes #5163 (commit)

• Allow legacy element property definitions with only a type. Fixes #5173 (commit)

• Update docs. (commit)

• Use Polymer.ResolveUrl.pathFromUrl (commit)

• Fix test under shadydom. Slight logic refactor. (commit)

• Fix lint warning (commit)

• Add importMeta getter to derive importPath from modules. Fixes #5163 (commit)

• Reference dependencies as siblings in tests. (commit)

• Update types (commit)

• Add note about performance vs correctness (commit)

• Update types. (commit)

• Lint clean. (commit)

• Pass through fourth namespace param on attributeChangedCallback. (commit)

• Add a @const annotation to help the Closure Compiler understand that Polymer.Debouncer is the name of a type. (commit)

• [ci skip] update changelog (commit)

• Update docs and types (commit)

• Update perf test to use strict-binding-parser (commit)

• Correct import paths (commit)

• Only store method once for dynamic functions (commit)

• Move strict-binding-parser to lib/mixins (commit)

• Rename to StrictBindingParser (commit)

• Fix linter errors (commit)

• Extract to a mixin (commit)

• Add missing dependency to bower.json (commit)

• Fix linter warning (commit)

• Add documentation (commit)

• Add performance test for binding-expressions (commit)

• Rewrite parser to use switch-case instead of functions (commit)

• Remove escaping from bindings (commit)

• Fix linter warning (commit)

• Refactor to be functional and add more tests (commit)

• Fix linter warnings (commit)

• Rewrite expression parser to state machine (commit)

Meaningful Changes

• Release all the intended Typescript typings

Raw Notes

• Add more missing .d.ts files from being npm published. (commit)

• [ci skip] update changelog (commit)

Meaningful Changes

• Include generated interfaces.d.ts in the npm package

Raw Notes

• Ensure generated interfaces.d.ts is included in npm package (commit)

• [ci skip] update changelog (commit)

Meaningful Changes

• Port gestures fixes w.r.t elements with disabled property from 2.x
• Ignore shady CSS scoping in getComposedHTML
• Typescript typings work again, as in 2.x
• Closure type fixups

Raw Notes

• rebuild package-lock (commit)

• Generate typings for Polymer 3. (commit)

• Revert Promise changes. (commit)

• Lint fixes. (commit)

• Restore some externs. (commit)

• Upstream a bunch of g3 changes. (commit)

• Add no-unused-vars eslint suppressions. (commit)

• Annotate another two ephemeral classes. (commit)

• Mark some ephemeral super classes as private. (commit)

• Annotate Node parameter as not null. (commit)

• Annotate some internal classes as private. (commit)

• Fix some appliesMixin annotations still with Polymer namespace. (commit)

• TypeScript generator config and extra interfaces for Polymer 3. (commit)

• Tweaks to make Polymer 3 more amenable to typings generation. (commit)

• Fix gulp 4 issues (commit)

• Extend Safari exceptions beyond 10.1 (commit)

• Ignore shady CSS scoping in getComposedHTML (commit)

• Fix method to force CE polyfill on in 3.x (commit)

• Convert object to class for better compilation (commit)

• Fix Typo in Readme (#5260) (commit)

• regen package-lock.json (commit)

• Update supported browsers in issue template (commit)

• Remove modulized comment (commit)

• Update package.lock (commit)

• Fix typo in jsdoc (#5248) (commit)

• Replace .npmignore with package.json "files" option. (#5245) (commit)

• Spelling (commit)

• Update template docs (#5233) (commit)

• fix lint (commit)

• Port disabled fixes from 2.x (commit)

• Update repo URL (commit)

• Add badges (commit)

• Update development instructions for 3.0 (#5226) (commit)

• [ci skip] update changelog (commit)

• Closure extern update (commit)

• Add user-importable files to bower.json's main field for modulizer. (commit)

Meaningful Changes

• Add manifest.json to aid with modulizer auto conversion.

Raw Notes

• Add back modulizer manifest (commit)

• [ci skip] update changelog (commit)

Meaningful Changes

• Forgot to actually remove importHref in 3.0.0, whoops!

Raw Notes

• [ci skip] update changelog (commit)

• Remove importHref from 3.0 (commit)

Breaking Changes

• As announced previously, we're using ES Modules now! You'll need to convert your HTML Imports files to modules either manually, or using our modulizer tool.
• With the ES Module change, a lot of API names have shortened now that they don't use the Polymer global. Here's an example:
  • Before:

    <link rel="import" href="polymer/lib/utils/case-map.html">
    <script>Polymer.CaseMap</script>
    

    After:

    import {CaseMap} from "@polymer/polymer/lib/utils/case-map.js";
    

• However, Polymer.Element became PolymerElement, as Element would shadow over the native Element class.
• importHref() functionality is removed, please use the ES Module equivalent: import('path/to/module.js' )
  • Polymer CLI tooling and Webpack will automatically fix this up for browsers that don't support ES Modules.

Raw Notes

• use released versions of shadycss and webcomponentsjs (commit)

• Bump dependencies (commit)

• Run Chrome & FF serially to try and help flakiness (commit)

• Fix lint warning (commit)

• Bump to cli 1.7.0 (commit)

• Removing support for returning strings from template getter. (Per previous documented deprecation: https://www.polymer-project.org/2.0/docs/devguide/dom-template#templateobject) (commit)

• Fix typos and nits (commit)

• Update to Gulp 4 (commit)

• Add serve command to package.json and update package-lock.json (commit)

• Fix for browsers that don't have input.labels. (commit)

• Tweak introductory note, fix webpack capitalization (commit)

• gestures: Avoid spreading non-iterable in older browsers (commit)

• wip (commit)

• Readme: very small tweaks (commit)

• Tweak wording. (commit)

• Fix link (commit)

• Re-order sections (commit)

• Fix LitElement typo (commit)

• Depend on polymer-cli rather than wct (commit)

• Minor tweaks (commit)

• Update README for 3.x (commit)

• Update Edge testing versions. (commit)

• Exclude all Edge versions from keyframe/font tests. (commit)

• Update wcjs version. (commit)

• Add .npmignore file (#5215) (commit)

• Use node 9 (commit)

• Use module flags for wct (commit)

• Use babel parser for aslant for dynamic import. (commit)

• Fix lint errors. (commit)

• 3.0.0-pre.13 (commit)

• [package.json] Remove version script (commit)

• Update dependencies (commit)

• Fix test typo on Chrome (commit)

• Fixes IE11 test issues (commit)

• Fixes styling tests related to using HTML Imports (commit)

• Remove crufty global (fixes globals.html test) (commit)

• Update to webcomponents 2.0.0 and webcomponents-bundle.js (commit)

• Fix meaningful whitespace in test assertion (commit)

• Fix latent mistake using old SD API (commit)

• Add global for wct callback when amd compiling (commit)

• Eliminate pre-module code from resolveUrl tests (commit)

• Improve documentation and legibility. (commit)

• Add some global whitelists (commit)

• Fix references to js files instead of html files (commit)

• Fix glob patterns for eslint (commit)

• Fix ESLint warnings (commit)

• Eliminate more canonical path usage (commit)

• Eliminate canonical path to wcjs (commit)

• Remove extra polymer-legacy.js imports (commit)

• Clean up Polymer fn import (commit)

• Add WCT config used by all tests (commit)

• Clean up exports (commit)

• Allow Polymer fn's call to Class to be overridden. (commit)

• add sill-relevant, deleted tests back in (commit)

• manually change inter-package dep imports from paths to names (commit)

• manually add assetpath (import.meta.url) for tests that require it (commit)

• move behavior definition to before usage (commit)

• define omitted class declaration (commit)

• remove < and replace with < for innerHTML (commit)

• fixed typo causing test to fail (commit)

• fix missing dom-module in modulization (commit)

• revert module wait (commit)

• wait for elements in other modules to be defined (commit)

• no more undefined.hasShadow (commit)

• removed link rel import type css tests (commit)

• delete debugger (commit)

• skip link rel import type css tests on native imports (commit)

• add missing css html import (commit)

• remove importHref tests (commit)

• Import Polymer function in tests from legacy/polymer-fn.js (commit)

• Export Polymer function from polymer-legacy.js (commit)

• Add new wct deps. (commit)

• Fixup a few places where comments were misplaced. (commit)

• Fixup license comments. (commit)

• Update package.json from modulizer's output, set polymer-element.js as main. (commit)

• Replace sources with modulizer output. (commit)

• Rename HTML files to .js files to trick git's rename detection. (commit)

• Delete typings for now. (commit)

• Add reasoning for suppress missingProperties (commit)

• Don't rely on dom-module synchronously until WCR. (commit)

• Avoid closure warnings. (commit)

• Add ability to define importMeta on legacy elements. Fixes #5163 (commit)

• Allow legacy element property definitions with only a type. Fixes #5173 (commit)

• Update docs. (commit)

• Use Polymer.ResolveUrl.pathFromUrl (commit)

• Fix test under shadydom. Slight logic refactor. (commit)

• Fix lint warning (commit)

• Add importMeta getter to derive importPath from modules. Fixes #5163 (commit)

• Reference dependencies as siblings in tests. (commit)

• Update types (commit)

• Add note about performance vs correctness (commit)

• Update types. (commit)

• Lint clean. (commit)

• Pass through fourth namespace param on attributeChangedCallback. (commit)

• Add a @const annotation to help the Closure Compiler understand that Polymer.Debouncer is the name of a type. (commit)

• [ci skip] update changelog (commit)

• Update docs and types (commit)

• Update perf test to use strict-binding-parser (commit)

• Correct import paths (commit)

• Only store method once for dynamic functions (commit)

• Move strict-binding-parser to lib/mixins (commit)

• Rename to StrictBindingParser (commit)

• Fix linter errors (commit)

• Extract to a mixin (commit)

• Add missing dependency to bower.json (commit)

• Fix linter warning (commit)

• Add documentation (commit)

• Add performance test for binding-expressions (commit)

• Rewrite parser to use switch-case instead of functions (commit)

• Remove escaping from bindings (commit)

• Fix linter warning (commit)

• Refactor to be functional and add more tests (commit)

• Fix linter warnings (commit)

• Rewrite expression parser to state machine (commit)

New Features

• Added the disable-upgrade feature from Polymer 1 as a mixin
• Add _shouldPropertiesChange method to customize when _propertiesChanged is called
  • This method gets the current, pending, and old property values and returns a boolean. If _shouldPropertiesChange returns true, _propertiesChanged is called.

Meaningful Changes

• <style include> values are now deduplicated to prevent unexpected conflicts
• static get template() {return null} can now be used to disable inheriting a template from a superclass
• tap gesture now correctly handles the disabled attribute
• click will no longer be squelched if a <label for> is tapped
• Support bindings to capitalized attributes:
  • Bindings of the form <svg viewBox="[[value]]">

Raw Notes

• Use function instead of Set (commit)

• [ci skip] Fix typo (commit)

• Fix test in shady DOM (commit)

• Deduplicate style includes (commit)

• use a clearer test for shadowRoot (commit)

• Returning null in template should nullify parent template (commit)

• [ci skip] Add clarifying comment (commit)

• Correct the JSBin version (commit)

• Put attribute capitalization fix in property-effects (commit)

• Add note about pre v3 releases (commit)

• Add note for npm package (commit)

• Add iron-component-page dev-dependency (commit)

• Update several gulp dependencies (commit)

• Update dom5 to 3.0.0 (commit)

• Update Google Closure Compiler version and fix cast (commit)

• Update types (commit)

• Fix several issues in the documentation of dom-* elements (commit)

• Handle disabled attribute correctly for tap gesture (commit)

• add test case for nested label (commit)

• Add docs and cleanup matchingLabels (commit)

• Add tests (commit)

• update types (commit)

• fix tests and add dependency import (commit)

• fix typings (commit)

• Ensure DisableUpgradeMixin extends PropertiesMixin (commit)

• Format comment and remove deduping mixin (commit)

• update types (commit)

• update types (commit)

• Add mixin to automatically detect capitalized HTML attributes (commit)

• Add instructions for locally viewing the source documentation (commit)

• Simplify condition checking in stylesFromModule function (commit)

• Bump type generator and generate new typings. (#5119) (commit)

• dispatchEvent returns boolean (#5117) (commit)

• Update types (commit)

• Fix license links (commit)

• Fix issue with not genering the Templatizer docs (commit)

• Bump TS type generator to pick up transitive mixin handling. (commit)

• Remove unnecessary mutableData property from MutableData mixin (commit)

• Update types (commit)

• Add note to updateStyles regarding updates to CSS mixins (commit)

• Avoid timing issues with polyfilled Promise (commit)

• Revert use of async/await due to lack of build/serve support. (commit)

• Revert types. (commit)

• Update eslint parserOptions to es2017 for async/await support. (commit)

• Use stronger check for PropertyEffects clients. Fixes #5017 (commit)

• Remove unneeded file (commit)

• [PropertiesChanged]: allow old data to be gc'd after _propertiesChanged (commit)

• Update package-lock.json (commit)

• Make Travis update-types failure style the same as the elements. (commit)

• Bump TypeScript generator version. (commit)

• Make EventApi.path EventTarget type non-nullable. (commit)

• Lint and type fixes (commit)

• [PropertiesChanged]: adds _shouldPropertiesChange (commit)

• Update docs: templatize() cannot be called multiple times (commit)

• [ci skip] update changelog (commit)

• Update types. (commit)

• Fix JSDoc example formatting (commit)

• Use latest webcomponents polyfill bundle (commit)

• Fix label tap by checking matched label pairs (commit)

• Defer creation related work via disable-upgrade (commit)

• lint fixes (commit)

• Adds Polymer.DisableUpgradeMixin (commit)

Meaningful Changes

• Fix a memory leak where element templates are cached on the prototype
• fix an expectation on event paths existing in gestures library
• Port scoped keyframe naming fix from 2.x

Raw Notes

• Improve comment. (commit)

• Add test. (commit)

• Make _template an actual

• Ensure template instance isn't cached on prototype. Fixes #5096 (commit)

• Port keyframe name fix from ShadyCSS (#5038) (commit)

• test if path exist with ghost clicks events (#4703) (commit)

• [ci skip] update changelog (commit)