How would I get a taxonomy/category list inside a Gutenberg block?

I would like to display a dropdown list of categories (or other taxonomy) inside of a Gutenberg block. I can only think of two ways to do this:

1. Create an array of the taxonomy in php and use wp_localize_script to make that data available to my block javascript.
2. Use fetch()? in the block to reach out to the api at /wp-json/wp/v2/categories/ and get all the categories.

Are one of these the preferred method? Is there some other kind of built-in or better way to do this?

Edit

As I continue to research this, I learned of another method available in the Gutenberg plugin and presumably available once this editor becomes part of core: wp.apiFetch(). Apparently, it’s a wrapper around fetch which hides away some of the unnecessary parts. Now I’m wondering if this is the preferred method.

3. Use wp.apiFetch() in the block to reach out to the REST api at /wp/v2/categories and get all the categories.

The Catch

On first glance, it seems to make more sense to use the apiFetch() function. However, because that’s asynchronous, the data doesn’t get loaded into the JSX element. I’m not sure how to make that data load into the element.

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Load the elements into a constant using a function like this:

const postSelections = [];

const allPosts = wp.apiFetch({path: "/wp/v2/posts"}).then(posts => {
    postSelections.push({label: "Select a Post", value: 0});
    $.each( posts, function( key, val ) {
        postSelections.push({label: val.title.rendered, value: val.id});
    });
    return postSelections;
});

Then use postSelections as your element “options”.

                    el(
                        wp.components.SelectControl,
                        {
                            label: __('Select a Post'),
                            help: 'Select a post to display as a banner.',
                            options: postSelections,
                            value: selectedPost,
                            onChange: onChangePost
                        }
                    ),

Method 2

You don’t need apiFetch or localization to get a list of all categories. You can do this with the wp.data module:

wp.data.select('core').getEntityRecords('taxonomy', 'category');

See the Gutenberg Handbook entry on Core Data for more details.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0