Program that shows performance degradation of graphQL when resolver returns a promise.

gql-test.js

/**
 * Program that shows performance degradation of graphQL when resolver returns a promise.
 * See Book.author() resolver below.
 * 
 * Usage: 
 * (1) run graphQL query with synchronous resolver
 * 	 node gql-test limit=100000 async=0
 * (2) run graphQL query with asynchronous resolver
 * 	 node gql-test limit=100000 async=1
 * Sample results:
 *  sync resolver: 603.922ms
 *  async resolver: 2541.374ms
 */

const { graphql, buildSchema } = require('graphql');

function getIntArg(argName) {
  const arg = process.argv.find(a => new RegExp(`^${argName}=`).test(a));
  if (arg) {
    return Number.parseInt(arg.split('=')[1], 10);
  }
}

// Test arguments
const args = {
  limit: getIntArg('limit') || 100000,
  async: getIntArg('async') || false
};

const schema = buildSchema(`
  type Author {
    name: String!
  }

  type Book {
    title: String!
    author: Author!
  }

  type Query {
    books(limit: Int!): [Book!]!
  }
`);


class Author {
  constructor(name) {
    this.name = name;
  }
}

const author = new Author('John Doe');

class Book {
  constructor(title) {
    this.title = title;
  }

  author() {
    if (args.async) {
      return Promise.resolve(author);
    }
    return author;
  }
}

const root = {
  books: ({limit}) => {
    const books = [];
    for (let i = 0; i < limit; i++) {
      books.push(new Book('Book:' + i));
    }
    return Promise.resolve(books);
  }
};

async function main() {
  const testName = args.async ? 'async resolver' : 'sync resolver';
  console.time(testName)
  await graphql(schema, `
    {
      books(limit: ${args.limit}) {
        title
        author {
          name
        }
      }
    }
  `, root);
  console.timeEnd(testName);
}

main();