shopify create private metafield to store app settings

[diandoli75]

I'm building an app for Shopify using Shopify CLI, Node and React I built a settings page, at the moment the layout is this:

I'm building an app for Shopify using Shopify CLI, Node and React I built a settings page, at the moment the layout is this: 

I'd like to save the value entered in API key field when I click on 'Save settings'. I think I could use private metafields to achieve this goal: shopify metafields 

I'm trying to add the field by means of graphQL and by using privateMetafieldUpsert as explained in the link

I'm stuck at this point

[jaikom]

Hey 

Did you ever figure out how to do this? I am trying to do something similar. Hope you have an answer?