* Add withCategories HOC and show API errors in Product Category Control
* Create withAttributes HOC and display errors in Product Attribute Control
* Refactor formatError so it handles JS errors and API errors
* Rename 'onSelectAttribute' with 'onExpandAttribute'
* Add and update tests
* Fix error in product attributes endpoint
* Refactor ProductCategoryControl into a functional component
* Refactor ProductAttributeControl into a functional component
* Refactor formatError to use a 'message' and 'type' properties
* Replace enzyme with TestRenderer
* Fix formatErrors doctype format
* Rename 'frontend' error type to 'general'
* Reset 'loaded' state in Featured Product and Category blocks
* Minor code improvements
* Remove state from ApiErrorPlaceholder
* Move getProduct to a HOC
* Undo changes in Featured Category
* Update proptypes
* Move error messages to <ApiErrorPlaceholder>
* Reorder props
* Move lifecycle methods to HOC
* Make <FeaturedProduct> component presentational
* Move withProduct to js/hocs
* Create NAMESPACE constant in utils
* Create getProduct util function
* Set 'error' and 'product' state to null instead of 'false' when they have no value
* Prevent getImageSrcFromProduct and getImageIdFromProduct returning an error when 'product' is not an object
* Add HOC tests
* Use 'toBe' and 'toBeNull' jest expect methods instead of 'toEqual' when possible
* Export HOCs from index
* Move mock implementation to beforeEach
Albert Juhé Lluveras