Field-level errors in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are field-level errors in GraphQL?

Field-level errors occur when a specific field in a GraphQL query fails, but the rest of the query can still return data successfully.

beginner

How does GraphQL handle errors for individual fields?

GraphQL returns partial data for the query and includes an 'errors' array describing the field-level errors, allowing clients to see which fields failed and why.

intermediate

Why are field-level errors useful in GraphQL?

They allow clients to receive as much valid data as possible even if some fields fail, improving user experience by showing partial results instead of failing the entire query.

intermediate

What does a typical GraphQL response with field-level errors look like?

It contains a 'data' object with available fields and an 'errors' array with details about which fields failed and error messages.

advanced

Can field-level errors affect nested fields in GraphQL?

Yes, errors can occur at any level of nesting, and GraphQL will return errors specific to the failing nested fields while still returning data for other parts.

What happens when a field-level error occurs in a GraphQL query?

A Only the failing field returns null and an error is reported.

B The client must retry the whole query.

C The server ignores the error and returns all data.

D The entire query fails and returns no data.

GraphQL returns null for the failing field and includes an error message in the 'errors' array, while returning data for other fields.

Where are field-level errors reported in a GraphQL response?

A Inside the 'data' object.

B In the HTTP status code.

C In the 'errors' array alongside 'data'.

D In a separate error log file.

Field-level errors are included in the 'errors' array in the GraphQL response, alongside the 'data' object.

If a nested field has an error, what does GraphQL return for that field?

A The entire parent object is null.

B The full nested object with errors inside.

C An empty string.

D Null for that nested field and an error message.

GraphQL returns null for the nested field that failed and includes an error message describing the problem.

Why might a client want to handle field-level errors instead of failing the whole query?

A To show partial data and improve user experience.

B To improve performance by ignoring errors.

C To avoid writing error handling code.

D To force the server to fix errors automatically.

Handling field-level errors allows clients to display available data and inform users about specific issues without losing all information.

Which of the following is true about field-level errors in GraphQL?

A They always cause the entire query to return null.

B They allow partial data to be returned with error details.

C They only occur on the root fields.

D They are not supported by GraphQL.

Field-level errors allow GraphQL to return partial data and include error details for the failing fields.

Explain what field-level errors are in GraphQL and how they affect the query response.

Think about how GraphQL handles errors without failing the whole query.

Describe why handling field-level errors is beneficial for client applications.

Consider what happens if the whole query fails versus partial failure.