Only load block assets on frontend when block exists.

[jamesmorrison]

Description of the Change

Adds conditional check that the block (Tabs / Tab Items) exist on the post before enqueueing assets.

Closes #199

How to test the Change

1. Create a page with the Tabs / Tab Items blocks
2. Verify these load on frontend without issue
3. Create a separate page without the Tabs / Tab Items blocks
4. Confirm the assets /dist/blocks/tabs-item-block.js and /dist/blocks/tabs-block.css are not enqueued

Changelog Entry

Fixed - Bug fix since 1.3.4 noted in #199

Credits

Props @jamesmorrison

Checklist:

• [x] I agree to follow this project's Code of Conduct.
• [ ] I have updated the documentation accordingly.
• [ ] I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• [ ] All new and existing tests pass.

[jamesmorrison]

@dkotter / @jeffpaul Please could you review this PR?

[jeffpaul]

I am curious though, looking at the original issue, why this ends up loading the block editor script at all on the front-end? Seems like there may be a bigger issue here with how this block is built/registered that may be worth changing to fix the problem here

@fabiankaegy any insights from your perspective on this?

[fabiankaegy]

I am curious though, looking at the original issue, why this ends up loading the block editor script at all on the front-end? Seems like there may be a bigger issue here with how this block is built/registered that may be worth changing to fix the problem here

@fabiankaegy any insights from your perspective on this?

Yeah ideally we should enqueue the assets via the viewScript field in block.json.

[jamesmorrison]

@jeffpaul / @dkotter / @fabiankaegy Sorry it's taken so long for me to make the requested changes here.

I've refactored this to use the viewScript; tested and working locally.

I chose to leave the frontend.js file in case it's needed, let me know if you'd like this removed.

Please could you review the updates here?