Why does "Cannot read property 'name' of undefined" error

[LeonYanghaha]

I executed the following code, but I got this error, which confused me. I don't have the name attribute. How could this error occur.

this is my query language

{
  node(id: 12) {
    id
    ...on User {
      username
    }
    ...on Blog {
      text
    }
  }
}

This is my code

const {makeExecutableSchema} = require('@graphql-tools/schema');
const {stitchSchemas} = require('@graphql-tools/stitch');
const {delegateToSchema} = require('graphql-tools');

let chirpSchema = makeExecutableSchema({
  typeDefs: `
    type User {
      # _id: ID!
      username: String
      blogs: [Blog]
    }
    
    type Blog {
      # _id: ID!
      user: User
      title: String!
      text: String
    }
    
    type Query {
      userById(id: ID!): User
      blogById(id: ID!): Blog
    }
     
    interface Node {
      id: ID!
    }
    
    extend type User implements Node {
      id: ID!
    }
    
    extend type Blog implements Node {
      id: ID!
    }
    
    extend type Query {
      node(id: ID!): Node
    }
  `,
  resolvers: {
    Query: {
      userById: (parent, {id}, context, info) => {
        return {id: 12, username: "yanghaha"};
      },
      blogById: () => {
        return {id: 122, title: "title", text: "text"};
      }
    }
  }
});

const typeDefs = stitchSchemas({
  subschemas: [{schema: chirpSchema}],
  resolvers: {
    Query: {
      node: (parent, {id}, context, info) => {
        const {type, localId} = deserializeGlobalId(id);
        let fieldName;
        if (type === 'Blog') {
          fieldName = 'blogById';
        } else if (type === 'User') {
          fieldName = 'userById';
        } else {
          throw new Error('Invalid global id');
        }
        return delegateToSchema({
          schema: chirpSchema,
          operation: 'query',
          fieldName,
          args: {id: localId},
          context,
          info,
        });
      },
    },
  }
});

const deserializeGlobalId = (id) => {
  if (id >= 10) {
    return {type: "Blog", localId: id}
  } else {
    return {type: "User", localId: id}
  }
};