Understanding how should we throw errors in GraphQL-based servers

Understanding how GraphQL throws errors is crucial for developers working with GraphQL. When an operation encounters an error, the GraphQL server throws an error response with detailed information about what went wrong. By familiarizing ourselves with the error-handling mechanism, we can effectively troubleshoot and improve the overall reliability of our GraphQL applications.

Let’s consider a simplified GraphQL schema that includes a Query type. Within this Query type, there is a field called withoutErrors. Take a look at the code of the schema:

type Post{
  title: String
  content: String
}
type PostResponse{
  posts: [Post!]!
}
type Query{
  withoutErrors: PostResponse
}

This schema should just returns PostResponse on the withoutErrors field.

Next, let’s code the resolver function for the withoutErrors field query. Here’s an example of resolver...