Earlier this week, Google announced that they have begun supporting JSON-LD structured data markup for Products and Reviews pages. In conjunction with the new support, Google has refined their requirements and the application logic used to evaluate those requirements. Per John Mueller, requirements for explicit reviewed item and correct property name values are now enforced.
This is welcome news from those of us in the SEO world, as JSON-LD is a much more readable, manipulable format for structured data.
Google’s Structured Data Testing Tool and the Search Console Structured Data Dashboard are available for evaluating structured data in all formats, including JSON-LD.