tabs: tab "{id}" - icon must be a single character or emoji, or an Element; got {got}. It is ignored. Markup is never parsed here: build the element and pass it instead.

Warnings reference › tabs.icon:*

Identifier

tabs.icon:*

Raised by

Tabs

Since

1.59.0

What happened

A tab's icon was neither a one-grapheme string nor a DOM element. The strip never parses markup for an icon - an HTML string handed to a tab label would be an injection route - so anything else is ignored and the tab renders without one. A multi-character string is reported with its length, because an emoji built from several code points that the browser does not combine is the commonest cause.

The fix

Pass a single character or emoji, or build an <svg>/<span> element yourself and pass the element.

The smallest fix

tabs: [{ id: 'open', title: 'Open', icon: '\u25CF' }]

Reference

Covered in full at the API reference.