Gutenberg: getEntityRecord returns null instead of undefined when an entity does not exist.

[herregroen]

Describe the bug
in Gutenberg 8.8 getEntityRecord and it's related functions ( getMedia etc. ) functions would return undefined when an entity didn't exist.

In Gutenberg 8.9 this now returns null. This is a backwards incompatible change as the recommended method by eslint to check for undefined is to do typeof value === "undefined" which returns false for null.

This will cause any plugin that previously made this check to start throwing errors as they'll be attempting property access on null. This can even cause the entire editor to crash, see https://github.com/Yoast/wordpress-seo/issues/15989.

To reproduce
Steps to reproduce the behavior:

1. Install Yoast SEO 14.9
2. Install Gutenberg 8.9
3. Visit a post in the editor that has a featured image set
4. See that the entire editor doesn't load.
5. Install Gutenberg 8.8.
6. See that no errors occur.

Expected behavior
Backwards incompatible changes should not be made to functions without proper notice and deprecation.

Editor version (please complete the following information):

• WordPress version: 5.5.1
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? Gutenberg plugin
• If the Gutenberg plugin is installed, which version is it? 8.9

Additional context

• The relevant change was introduced here: https://github.com/WordPress/gutenberg/pull/19498/files#diff-ea600cd29f004c4af8849b3bd82f0342R122

[aristath]

Issue was identified and reported by others too on https://github.com/WordPress/gutenberg/issues/25033

[regevbr]

Thanks so much for the swift response! I can confirm that 8.9.1 solved the issue