[bw_show_googlemap] leads to Uncaught ReferenceError: google is not defined

bobbingwide commented 7 years ago

Sometimes when viewing content which contains the [bw_show_googlemap] shortcode the Google map is not displayed. The problem occurs when Yoast SEO is activated.

Expected output

Use of the [bw_show_googlemap] shortcode in post content should lead to the display of a Google Map.

Actual output

The Google map appears blank.
Google chrome's Console contains
```
Uncaught ReferenceError: google is not defined at initialize2 (?oik-tab=course:257)
```
Explanation

During display of the content Yoast SEO attempts to determine the content to use in meta property tags. Some of this content is determined from the value for the Meta description ( meta_key=_yoast_wpseo_metadesc ). If this post meta data is not set Yoast SEO attempts to determine it using get_the_excerpt().
get_the_excerpt() can cause the the_content filter to be executed
this leads to [bw_show_googlemap] being expanded.
the logic in bw_googlemap_v3() generates JavaScript which it assumes will be output to the browser.
but Yoast SEO's logic doesn't output the final result of the_content filters.
however, subsequent invocations of the [bw_show_googlemap] shortcode rely on the output from the first invocation.
so when the_content is performed for the actual display, the first lump of JavaScript is missing.
hence the Uncaught ReferenceError

Workaround

Write a Meta description using the Yoast SEO meta box Edit snippet button
Write an excerpt.
Follow the plugin's advice as found in the HTML comment it generates

Admin only notice: this page doesn't show a meta description because it doesn't have one, either write it for this page specifically or go into the SEO -> Titles menu and set up a template.

Setting up the template for each post type is the easiest workaround to implement as it will apply for every affected post.

Proposed solution

Yoast SEO tries to get a value for _yoast_wpseo_metadesc for every page being displayed. It's more efficient for the _yoast_wpseo_metadesc field to be populated when the post is saved; save once - display many.

This is true for every page, regardless of the shortcodes that may or may not be used in the content / generated content. So our solution should automatically set _yoast_wpseo_metadesc if it's not already set.

I don't think we need to test whether or not Yoast SEO is activated.

Alternative solution

Change the shortcode to enqueue the JavaScript so that the workaround is not required.

bobbingwide commented 4 years ago

I don’t think I changed anything but I can’t reproduce the problem using my iPad on cwiccer.com with the Google Maps block in a post. There is a simple explanation. Within the logic to get_the_excerpt(), called by WordPress SEO to determine the Opengraph description, is a call to excerpt_remove_blocks(). This allows core/paragraph block and other blocks, but not the oik-block/googlemap block. WordPress SEO therefore doesn't cause the [bw_show_googlemap] shortcode to be expanded as it's been stripped from the content.

When the shortcode is added directly, in a paragraph block, then it'll get expanded. Another workaround would be to include the shortcode in a shortcode block.

So that's two more workarounds.

Use the Google Maps block - oik-block/googlemap
Use the Shortcode block. - core/shortcode

bobbingwide commented 4 years ago

Maybe I should just write a FAQ about this. Concentrate on the other challenges when content is expanded during REST API processing.

bobbingwide / oik