New Features

• Added Polymer.htmlLiteral tagged template literal function to safely include non-<template> variables in Polymer.html templates.

  // Example
  const title = Polymer.htmlLiteral`World!`;
  class LiteralElement extends Polymer.Element {
    static get template() {
      return Polymer.html`<span>Hello ${title}</span>`
    }
  }

  • Note: This is now the only way to include literals in Polymer.html strings
• Allow use of templatizer without an owner & host property

Meaningful Changes

• Fix unintended behavior change in Polymer.ResolveUrl.resolveUrl() by again allowing urls beginning with # and / to be treated as absolute URLs.
  • If you want a more standard URL handling behavior, please use new URL()
• Fix observers being called twice
• Ensure path notifications from templatized instances don't throw
• Fix differences between this.slice() and Array.prototype.slice()

Raw Notes

• Update types (commit)

• Update JSDocs to use tags (commit)

• Fix type declarations inadvertedtly referencing Polymer.Element. (#5084) (commit)

• Use class syntax in documentation (#5077) (commit)

• Add hash/abs URL resolution tests. (commit)

• Update types. (commit)

• Add comments about resolveUrl idiosyncrasies. (commit)

• Revert "Move absolute url logic to element-mixin" (commit)

• Added Polymer.version to polymer-externs (#5079) (commit)

• Avoid tracking parentNode since it's unncessary (commit)

• Update types. (commit)

• Fix nit. (commit)

• Avoid comment constructor for IE support. (commit)

• Disallow non-templates as interpolations in Polymer.html (#5023) (commit)

• Exclude index.html from type generation. (#5076) (commit)

• update types (commit)

• [element-mixin] Do not create property accessors unless a property effect exists (commit)

• Use containers for testing again (#5070) (commit)

• Invoke JS compiler rename for properties (commit)

• Add package-lock.json back (commit)

• fix test. (commit)

• Enhance robustness by replacing slot with a comment (commit)

• Avoid use of element accessors on doc frag to fix IE/Edge. (commit)

• Fix linter errors (commit)

• Fix issue with observers being called twice (commit)

• Revert package-lock change (commit)

• [ci-skip] Update changelog (2.4.0) (commit)

• Add package-lock.json to .gitignore (commit)

• Update types (commit)

• Add comments re: instanceProps (commit)

• Change if-condition to check for arguments.length (commit)

• Delete package-lock.json (commit)

• [ci skip] Fix test case name (commit)

• Fix issue where el.splice could not clear full array (commit)

• Make owner optional as well. (commit)

• Update package-lock.json (commit)

• Update typescript types again, after fixing jsdoc. (commit)

• Fix lint warnings. (commit)

• Update typescript types. (commit)

• Ensure path notifications from templatized instances don't throw. Fixes #3422 (commit)

• Allow templatizer to be used without owner or host prop forwarding. Fixes #4458 (commit)

• Templatize: remove slots when hiding children (commit)

• Clarify API docs for PropertyAccessors mixin (commit)