@apollographql/apollo-tools

What is @apollographql/apollo-tools?

@apollographql/apollo-tools is a utility library for building GraphQL servers with Apollo. It provides tools for schema manipulation, validation, and other common tasks needed when working with GraphQL schemas.

What are @apollographql/apollo-tools's main functionalities?

Schema Validation

This feature allows you to validate a GraphQL schema to ensure it adheres to the GraphQL specification. The code sample demonstrates how to parse a schema and validate it using the `validateSDL` function.

const { validateSDL } = require('@apollographql/apollo-tools');
const { parse } = require('graphql');

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

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

Schema Transformation

This feature allows you to transform an existing GraphQL schema. The code sample shows how to create an executable schema and then transform it to modify the resolver for the `hello` field.

const { transformSchema } = require('@apollographql/apollo-tools');
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: {
    hello: {
      resolve: () => 'Hello transformed world!',
    },
  },
});

console.log(transformedSchema.getQueryType().getFields().hello.resolve());

Schema Merging

This feature allows you to merge multiple GraphQL schemas into a single schema. The code sample demonstrates how to create two separate schemas and then merge them into one.

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

const schema1 = makeExecutableSchema({
  typeDefs: `
    type Query {
      hello: String
    }
  `,
  resolvers: {
    Query: {
      hello: () => 'Hello from schema1!',
    },
  },
});

const schema2 = makeExecutableSchema({
  typeDefs: `
    type Query {
      world: String
    }
  `,
  resolvers: {
    Query: {
      world: () => 'World from schema2!',
    },
  },
});

const mergedSchema = mergeSchemas({ schemas: [schema1, schema2] });

console.log(mergedSchema.getQueryType().getFields().hello.resolve());
console.log(mergedSchema.getQueryType().getFields().world.resolve());

Other packages similar to @apollographql/apollo-tools

graphql-tools

graphql-tools is a comprehensive toolkit for building, mocking, and transforming GraphQL schemas. It offers similar functionalities to @apollographql/apollo-tools, such as schema stitching, schema transformation, and schema validation. It is widely used in the GraphQL community and provides a robust set of features for schema manipulation.

graphql-compose

graphql-compose is a toolkit for generating complex GraphQL schemas in an easy and maintainable way. It provides utilities for schema creation, schema transformation, and schema merging. Compared to @apollographql/apollo-tools, graphql-compose offers a more composable approach to building GraphQL schemas, making it easier to manage large and complex schemas.

nexus

Nexus is a code-first GraphQL schema construction library for JavaScript/TypeScript. It allows you to define your GraphQL schema using code, which can be more intuitive and maintainable than SDL (Schema Definition Language). While @apollographql/apollo-tools focuses on SDL-based schema manipulation, Nexus provides a code-first approach, which can be more suitable for developers who prefer to work directly with code.