Mutation observer wouldn't fire in certain situations

[joshleblanc]

In certain situations where you're morphing an element that does not contain a data-reflex attribute, the mutation observer wouldn't fire.

Type of PR (feature, enhancement, bug fix, etc.)

bug fix

Description

The attributeFilter option of mutation observer checks that any changed element has any attribute in the list of filters. If you morph an element without a data-reflexattribute, this mutation observer won't fire.

@leastbad's note: adding actionAttribute to the list of observed attributes is a viable solution because setupDeclarativeReflexes adds __perform, a private/internal action. This makes it a reliable litmus test for the edge case this PR addresses.

Checklist

• My code follows the style guidelines of this project
• Checks (StandardRB & Prettier-Standard) are passing
• This is not a documentation update