Disable Preview button when post type doesn't support it

[danielbachhuber]

Description

In the classic editor, the preview button is only available if is_post_type_viewable returns true. We are updating the logic to follow the same behavior.

Fixes #5749

Previously #5770

How Has This Been Tested?

Register a post type with publicly_queryable set to false.
E.g:

function create_product_type() {
    register_post_type( 'acme_product',
        array(
			'label'  => 'Product',
            'labels' => array(
                'name' => __( 'Products' ),
                'singular_name' => __( 'Product' )
            ),
            'public' => true,
			'show_in_rest' => true,
			'publicly_queryable' => false,
        )
    );
}
add_action( 'init', 'create_product_type' );

Verify preview button is not available for posts of this Post Type.

[danielbachhuber]

I've done what I think should work, but I'm still running into what I think is a simple error:

The above error occurred in the <WithSelect(IfCondition(Connect(t)))> component:
    in WithSelect(IfCondition(Connect(t)))
    in div
    in div
    in Unknown (created by WithDispatch(Component))
    in WithDispatch(Component) (created by WithSelect(WithDispatch(Component)))
    in WithSelect(WithDispatch(Component))
    in div
    in Unknown (created by WithViewportMatch(Component))
    in WithViewportMatch(Component) (created by n)
    in div (created by n)
    in n (created by WithDispatch(n))
    in WithDispatch(n) (created by WithSelect(WithDispatch(n)))
    in WithSelect(WithDispatch(n))
    in t
    in r (created by t)
    in t (created by t)
    in t (created by t)
    in t (created by t)
    in t (created by t)
    in t

React will try to recreate this component tree from scratch using the error boundary you provided, t.
react-dom.b69cca96.js:10003:5
TypeError: e(...).getPostType(...) is undefined[Learn More]
index.js:17:66194
TypeError: e(...).getPostType(...) is undefined[Learn More]
index.js:17:66194

Is there some simple mistake I'm making?

[pento]

Everything in the connect() should be moved to the withSelect(). This also avoids having to import getEditedPostAttribute() twice.

[danielbachhuber]

I'm not sure I follow. Can you clarify what you mean by this, or point me to an example?

[pento]

Sure, check out the withSelect() usage in the post title component.

Anything that's coming from the editor selectors should be returned from the withSelect() function. For example, the current modified: getStateEditedPostAttribute( state, 'modified' ) in connect() would be moved to the object returned from the withSelect() function, so it becomes:

return {
	isPreviewable: get( postType, 'viewable', false ),
	modified: getEditedPostAttribute( 'modified' ),
};

The same thing can be repeated for all of the items in the connect().

[pento]

You can use get( postType, 'previewable', false ) here, rather than having the inline check.

[pento]

Actually, should probably just access it as postType.previewable, without the postType &&, as the posttype should always be retrieved in edit context.

[danielbachhuber]

Updated.

[pento]

Is there are particular reason for calling it "previewable", rather than "viewable"? I added a similar flag in this PR: https://github.com/WordPress/gutenberg/pull/5756/files#diff-6ff32417da0658502e7caa1a1abbeae6R403

But "previewable" is not quite the flag name I'd be using in that case.

[danielbachhuber]

No particular reason. Changed it to viewable.

[pento]

Noice. I shamelessly stole this and merged it in 4c90150, so it doesn't need to be in this PR anymore.

[danielbachhuber]

@pento What opinions or suggestions do you have on how this should be tested?

[danielbachhuber]

This is going to conflict with #6167

[pento]

I'd split the testing into two parts:

• Test that the API returns the correct viewable value for different post types.
• Test that the button is disabled when the isPreviewable prop is false. Check the tests for this component, there are some examples of props being manually overridden in the tests.

[danielbachhuber]

Closing in favor of #6232