Problem with Metafield value type JSON

[Av18]

Hello, 

I need to figure out one issue with the metafield which has value type =  'json'.

metafield = ShopifyAPI::Metafield.new

metafield.variant_id = custom_bundle.master_variant_id

metafield.namespace = 'custom_bundle'

metafield.key = 'product_data'

metafield.value = child_products_data.to_json

metafield.type = 'json'

metafield.save!

When child_products_data is empty then metafield.value set the value as [].

instead of [] in the metafield, how can I set it completely blank.

like:  

From API call I can not sent nil value for metafield.value if child_products_data is empty, because it gives error like #<ShopifyAPI::Errors::HttpResponseError: {\"errors\":{\"value\":[\"can't be blank.\"]}.

Have any solution for this?? 

[SBD_]

Hey @Av18 

I looked into how the native admin handles this, and it appears metafields are simply deleted when their value is removed.

E.g. With bundle value:

With blank bundle value:

[Av18]

Hey @SBD_ 

You are correct. Metafields are simply deleted when their value is removed. However, this only works for metafields that do not have a JSON type. For JSON type metafields, updating a nil value is prevented.

For example

when I update metafield.value 

metafield.value = child_products_data.to_json

metafield.type = 'json'

metafield.save!

to this metafield.value = nil

then it prevent like {\"value\":[\"can't be blank.\"]}.

[SBD_ · Accepted solution]

Hey @Av18 

Thanks for the response. I just tried with a JSON field and saw the same results.

E.g. Here's a json field

Which the API returns as:

But setting it to blank in admin (or running metafieldDelete / REST `delete`) clears the value:

I.e. try .delete instead of .save of a nil value.

Let me know if I'm not following 🙂

[Av18]

Hey @SBD_ 

"Thank you for providing the correct solution."

It successfully clears the values when I delete the metafield.