GraphQL Interview Questions and Answers
Related differences
Ques 21. How does GraphQL handle circular dependencies in schemas?
GraphQL allows the use of forward and backward references in a schema, but circular dependencies can be resolved using lazy loading or by using the `GraphQLObjectType` constructor to create types that reference each other.
Ques 22. What is the purpose of the `__typename` field in GraphQL?
The `__typename` field in GraphQL is automatically included in every object type and represents the name of the type. It is useful for client-side caching and identifying the type of an object in a polymorphic relationship.
Ques 23. Explain the concept of a union type in GraphQL.
A union type in GraphQL allows a field to return different types of objects. It is useful when a field can have multiple types, and the client needs to handle each type differently.
Ques 24. What is the role of the `!` (exclamation mark) in GraphQL type definitions?
The `!` in GraphQL type definitions indicates that a field is non-nullable, meaning it must always have a value. It is used to express the presence of required data.
Ques 25. How does GraphQL handle security concerns, such as denial-of-service attacks?
To mitigate security concerns, GraphQL implementations often include features like query complexity analysis and depth limiting. These measures prevent overly complex or deep queries that could lead to denial-of-service attacks.
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