Packages

@lwc/synthetic-shadow

9.5.3 · 27 Oct 2026MIT276.2k / weekRepositoryHomepagenpmAtom feed

Your version

1.2.0

23 Jan 2020Where it was published

1.18.0 is the newest release of 1.x.

In short

2 removed1 deprecated2 new2 fixed3 changed2 internal

  • removed

    #1648 - engine: Remove the instanceof Event check in LightningElement.prototype.dispatchEvent. The same check is run by the browser when invoking the EventTarget.prototype.dispatchEvent method. Reduces the coupling between the engine and the DOM in preparation for server side rendering.

  • removed

    #1694 - features: Remove support for feature flags as computed properties. This means that featureFlags['ENABLE_FOO'] will no longer work and should be referenced as featureFlags.ENABLE_FOO instead.

  • deprecated

    #1679 - wire-service: Add support for the lowercase event type wirecontextevent in addition to the currently supported event type WireContextEvent. This allows component authors to avoid engine warnings triggered when using event types with capital letters. WireContextEvent is now deprecated and will be removed in a future release.

Release note

Improvements

  • #1687 - template-compiler: Add support for content attributes with leading hyphens. Until now, component authors were able to define component properties in Pascal case but users were not able to set those properties in their templates. Users can now set the value of a Pascal case property by adding a leading hyphen to the attribute (e.g., @api FooBar can be set via -foo-bar={awesomeValue})

  • deprecated

    #1679 - wire-service: Add support for the lowercase event type wirecontextevent in addition to the currently supported event type WireContextEvent. This allows component authors to avoid engine warnings triggered when using event types with capital letters. WireContextEvent is now deprecated and will be removed in a future release.

Bug Fixes

  • #1676 - synthetic-shadow: Fix a bug in the Event polyfill so that the composed option is respected when instantiating an instance of Event. The previous behavior ignored the composed option and only considered the type of the event when accessing the composed property of an Event instance. This polyfill exists to normalize the behavior of some browsers that incorrectly set the composed property of natively composed events.

Internal

  • #1682: Remove usage of white/black as good/bad. Implements the “tone” guidelines for the WHATWG style guide.

  • removed

    #1648 - engine: Remove the instanceof Event check in LightningElement.prototype.dispatchEvent. The same check is run by the browser when invoking the EventTarget.prototype.dispatchEvent method. Reduces the coupling between the engine and the DOM in preparation for server side rendering.

  • #1692 - engine: Refactor the way error boundaries are computed by decoupling the logic from the DOM.

  • #1683 - features: Fix a bug where unary negation of a runtime feature flag was being interpreted as a compile-time boolean false.

  • engine: Improve our usage of internal types.

  • removed

    #1694 - features: Remove support for feature flags as computed properties. This means that featureFlags['ENABLE_FOO'] will no longer work and should be referenced as featureFlags.ENABLE_FOO instead.

  • #1652 - synthetic-shadow: Add tsc as part of the build. tsc should run before rollup to catch TypeScript-related errors.