apollo-graphql

What is apollo-graphql?

The apollo-graphql npm package provides a set of utilities for working with GraphQL schemas and operations. It is part of the Apollo ecosystem and is designed to help developers build, transform, and analyze GraphQL schemas and queries.

What are apollo-graphql's main functionalities?

Schema Transformation

This feature allows you to transform an existing GraphQL schema. In this example, we create a simple schema with a 'hello' query and then transform it to change the resolver for the 'hello' field.

const { transformSchema } = require('apollo-graphql');
const { makeExecutableSchema } = require('@graphql-tools/schema');

const typeDefs = `
  type Query {
    hello: String
  }
`;

const resolvers = {
  Query: {
    hello: () => 'Hello world!',
  },
};

const schema = makeExecutableSchema({ typeDefs, resolvers });

const transformedSchema = transformSchema(schema, {
  Query: {
    fields: {
      hello: {
        resolve: () => 'Hello transformed world!',
      },
    },
  },
});

console.log(transformedSchema);

Schema Validation

This feature allows you to validate a GraphQL schema. In this example, we build a simple schema and then validate it, logging any validation errors to the console.

const { validateSchema } = require('apollo-graphql');
const { buildSchema } = require('graphql');

const schema = buildSchema(`
  type Query {
    hello: String
  }
`);

const errors = validateSchema(schema);

if (errors.length > 0) {
  console.error('Schema validation errors:', errors);
} else {
  console.log('Schema is valid');
}

Operation Parsing

This feature allows you to parse a GraphQL operation (query, mutation, or subscription). In this example, we parse a simple query operation and log the parsed operation to the console.

const { parseOperation } = require('apollo-graphql');

const operation = `
  query GetHello {
    hello
  }
`;

const parsedOperation = parseOperation(operation);

console.log(parsedOperation);

Other packages similar to apollo-graphql

graphql-tools

The graphql-tools package provides a set of utilities for building and manipulating GraphQL schemas. It offers similar functionalities to apollo-graphql, such as schema transformation and stitching, but is more focused on schema creation and merging.

graphql

The graphql package is the core reference implementation of the GraphQL specification. It provides the essential tools for defining and executing GraphQL queries, but does not include the higher-level utilities found in apollo-graphql.

graphql-compose

The graphql-compose package provides a set of tools for building and modifying GraphQL schemas using a more composable approach. It offers similar functionalities to apollo-graphql, such as schema transformation and validation, but with a focus on composability and ease of use.

README

apollo-graphql