No, it is not possible to use inheritance with GraphQL input types according to the GraphQL specification. The GraphQL type system does not support any form of inheritance for input types. This means that input types cannot implement interfaces or extend other input types in the same way that object types can. The specification is intentionally constrained to maintain simplicity and avoid complexity in schema design[2][4][6].
However, there are some workarounds and alternative approaches that developers can use to achieve similar functionality:
Composition Over Inheritance: Instead of using inheritance, you can use composition to include common fields in multiple input types. This involves creating a separate input type for the common fields and then including it as a field in other input types[2].
Custom Directives: Some developers create custom directives to programmatically append common fields to input types based on metadata. This approach requires additional implementation effort but can help reduce redundancy[2][4].
Type Extensions: Starting with the June 2018 version of the GraphQL specification, it is possible to extend an existing input type by adding new fields to it. However, this is not true inheritance, as it does not allow creating new types based on existing ones[2].
TypeGraphQL: In TypeGraphQL, a library for building GraphQL APIs with TypeScript, you can use class inheritance to define input types. This appr...
