Determine why a Union type wasn't used in graphql schema #105

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dboreham · 2023-05-16T12:45:37Z

dboreham commented

2023-05-16 12:45:37 +00:00

Our GraphQL endpoint returns registry records conforming to a property set schema with Value type defined here.

This is a struct or "sum" type, where all of string, json, reference are present but by convention all except one is null.
This is a way of implementing a variant, union, or "product" type.

But GraphQL has union types.
Curious to understand why we didn't use that capability.

Our GraphQL endpoint returns registry records conforming to a property set schema with `Value` type [defined here](https://github.com/cerc-io/laconicd/blob/main/gql/vulcanize/chiba-clonk/schema.graphql#L41). This is a struct or "sum" type, where all of `string`, `json`, `reference` are present but by convention all except one is null. This is a way of implementing a variant, union, or "product" type. But GraphQL [has union types](https://graphql.org/learn/schema/#union-types). Curious to understand why we didn't use that capability.

roysc commented

2023-09-22 13:20:35 +00:00

I suspect the answer relates to the fact that when defining a GraphQL union, all variants must be other objects, not scalars. So, we would have to wrap everything like IntVariant for int, etc. and perhaps that amount of boilerplate was deemed not worth it - I think @ashwinphatak's team would have to confirm, though.

(And to be pedantic, a sum type would be a union, what we have now is a product type)

I suspect the answer relates to the fact that when defining a GraphQL union, all variants must be other objects, not scalars. So, we would have to wrap everything like `IntVariant` for int, etc. and perhaps that amount of boilerplate was deemed not worth it - I think @ashwinphatak's team would have to confirm, though. (And to be pedantic, a sum type would be a union, what we have now is a product type)