What is the current behavior?

When @Prop({ reflect: true }) something is set via a property to undefined
(e.g. document.querySelector('my-thing').something = undefined) this causes the expected re-render but also causes the corresponding attribute to be removed (e.g. cmp.removeAttribute('something')) which in-turn causes the property to be set to null, causing a double re-render which can cause errors

GitHub Issue Number: #6396

What is the new behavior?

Fixes #6396

Now, when an attribute change reflects back to it's property the assessment is null == undefined (instead of null === undefined)

Documentation

Does this introduce a breaking change?

• Yes
• No

Testing

Other information