What arguments does a GraphQL resolver receive?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of GraphQL conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
A resolver has the signature (parent, args, context, info):
parent(also root/value): the object returned by the parent resolver.args: the arguments supplied to this field, already coerced to schema types.context: a per-request object for shared state such as the authenticated user, database clients and DataLoaders. It is created once per request and is where authorization and tracing are usually wired.info: metadata about the execution, including the field name, return type, path and query AST, useful for logging and projection optimization.
const resolvers = {
Query: {
user: (_, { id }, ctx) => ctx.db.user.findById(id),
},
};
For a default-returning field you can often omit the resolver. Keep resolvers thin: validate and authorize, delegate to services, and avoid embedding business logic that cannot be reused or unit-tested without a GraphQL layer.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
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