I'm working on a store where the owner wants to remove OOTS' Turbo theme's inbuilt JSON as they have the JSON-LD for SEO app and currently, the markup is showing as two products. As per https://www.littlestreamsoftware.com/articles/removing-invalid-microdata-shopify-theme, it's not a biggie to have both in there, but can cause issues with Google Merchant Center which we use.
My question is, has anyone come across this issue before and can speak to how much work is involved removing the theme's microdata and JSON-LD? ... Before I embark on this work!
Google Merchant Center only reads the first structured data, all preceding data is not read.
I've done this with a couple themes, the microdata is harder to get. My approach is to download the theme, then use Notepad++ to search through the entire theme folder for "itemprop". Then carefully remove it without breaking the HTML it may be embedded into, case-by-case. Then combo of spot checks like the Structured Data Testing Tool and a crawl tool like ScreamingFrog or Sitebulb to find any lingering schema issues.
In my case took about ~25 replacements per theme, so a couple hours all up with testing, as long as you know what you're doing and don't break stuff. Then you gotta monitor what happens in the SERPs, things like price & reviews display is harder to track, so I'd also recommend taking a snapshot of 10-20 products and how they are displaying. Then recheck SERPs in a week.
Also, the JSON-LD for Shopify app that LSS makes pretty nice schema. It's my goto for JSON-LD atm, primarily for the aggregate review sync functionality.