GraphQL error format - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

What is the output error message format for a GraphQL query with a syntax error?

Consider a GraphQL query with a missing closing brace. What does the error response look like?

GraphQL

query { user(id: 1) { name }

A {"errors":[{"message":"Syntax Error: Expected Name, found <EOF>","locations":[{"line":1,"column":26}]}]}

B {"error":"Syntax error at line 1"}

C {"message":"Unexpected end of query"}

D {"errors":[{"msg":"Missing closing brace"}]}

💡 Hint

GraphQL errors include an 'errors' array with detailed message and location.

GraphQL returns errors as an array under 'errors' with 'message' and 'locations' keys describing the problem.

❓ query_result

intermediate

What does a GraphQL error response contain when a requested field does not exist?

If a query asks for a field 'age' on a type that does not have it, what error response is returned?

GraphQL

query { user(id: 1) { age } }

A {"message":"Invalid field age"}

B {"error":"Field age not found"}

C {"errors":[{"message":"Cannot query field \"age\" on type \"User\".","locations":[{"line":1,"column":15}]}]}

D {"errors":[{"msg":"Field age missing in schema"}]}

💡 Hint

GraphQL error messages specify the field and type causing the issue.

GraphQL errors specify the exact field and type that caused the error with location info.

📝 Syntax

advanced

Which option correctly shows the GraphQL error format for a validation error with multiple errors?

A query has two errors: a missing field and a wrong argument type. What is the correct error response format?

GraphQL

query { user(id: "abc") { name age } }

A {"errors":[{"message":"Argument \"id\" has invalid value \"abc\".","locations":[{"line":1,"column":13}]},{"message":"Cannot query field \"age\" on type \"User\".","locations":[{"line":1,"column":25}]}]}

B {"errors":[{"msg":"Invalid id argument"},{"msg":"Field age missing"}]}

C {"error":"Multiple errors found"}

D {"errors":[{"message":"id argument error"},{"message":"age field error"}]}

💡 Hint

GraphQL errors list each error with message and location in an array.

GraphQL returns multiple errors as objects in the 'errors' array with detailed messages and locations.

🧠 Conceptual

advanced

What key fields are always present in a GraphQL error object?

Select the fields that are always included in each error object returned by a GraphQL server.

A "error" and "code"

B "message" and "locations"

C "msg" and "line"

D "description" and "position"

💡 Hint

Look for the standard keys used in GraphQL error objects.

GraphQL error objects always include 'message' describing the error and 'locations' showing where it happened.

🔧 Debug

expert

Why does this GraphQL error response cause a client parsing failure?

Given this error response: {"errors":[{"message":"Field 'name' not found"}]} but the client expects 'locations' field as well, what is the issue?

A The JSON is invalid because of missing commas.

B The 'message' field is incorrectly formatted as a string instead of an object.

C The 'errors' key should be a string, not an array.

D The error object is missing the required 'locations' field, causing client parsing failure.

💡 Hint

GraphQL clients expect a consistent error object structure.

GraphQL error objects must include 'locations' to indicate where the error occurred; missing it can break clients expecting it.