Gutenberg: Using wp.blocks.registerBlockStyle() adds `is-style-undefined`

[carrieforde]

Describe the bug
I am tying to add a tip style to the paragraph block by using wp.blocks.registerBlockStyle( 'core/paragraph', 'tip' ), but within both the editor and the front end, the class added ends up being is-style-undefined. I have also tried the example provided in the documentation for the quote, but am seeing the same issue.

I know the script I've added is firing because I see I have the option to add a style:

but it isn't consistent with blocks that have the styles object at time of registration (e.g. core/button):

To Reproduce

1. Add wp.blocks.registerBlockStyle( 'core/paragraph', 'tip' ); to a theme or plugin.
2. Add a new paragraph to a post or page.
3. Try changing the style to tip.
4. Use the devtools to see that is-style-undefined is applied to the block.

Expected behavior
Adding a tip style should add the is-style-tip class to the paragraph block when it is selected.

Screenshots
See above.

Additional context

• Gutenberg 3.9

[joemaller]

@carrieforde the documentation for wp.blocks.registerBlockStyle needs updating. A plain string doesn't work for the second argument. Try the following instead and you should get the is-style-tip style:

wp.blocks.registerBlockStyle( 'core/paragraph', {
    name: 'tip',
    label: 'Tip'
} );

I've got a PR open to update that documentation page: https://github.com/WordPress/gutenberg/pull/10163

[carrieforde]

@joemaller Thanks so much. 💯 That most certainly did the trick.