jsonGraphqlExpress.ts

import { createHandler } from 'graphql-http/lib/use/express';
import schemaBuilder from './schemaBuilder';
import { graphiqlHandler } from './graphiqlHandler';
import type { Data } from './types';
import type { Handler } from 'express';

/**
 * An express middleware for a GraphQL endpoint serving data from the supplied json.
 *
 * @param {any} data
 * @returns An array of middlewares
 *
 * @example
 * import express from 'express';
 * import jsonGraphqlExpress from 'json-graphql-server';
 *
 * const data = {
 *    "posts": [
 *        {
 *            "id": 1,
 *            "title": "Lorem Ipsum",
 *            "views": 254,
 *            "user_id": 123,
 *        },
 *        {
 *            "id": 2,
 *            "title": "Sic Dolor amet",
 *            "views": 65,
 *            "user_id": 456,
 *        },
 *    ],
 *    "users": [
 *        {
 *            "id": 123,
 *            "name": "John Doe"
 *        },
 *        {
 *            "id": 456,
 *            "name": "Jane Doe"
 *        }
 *    ],
 * };
 *
 * const PORT = 3000;
 * var app = express();
 *
 * app.use('/graphql', jsonGraphqlExpress(data));
 *
 * app.listen(PORT);
 */
export default (data: Data) => {
    const graphqlHandler = createHandler({
        schema: schemaBuilder(data),
    });

    const expressMiddleware: Handler = (req, res, next) => {
        if (req.is('application/json')) {
            return graphqlHandler(req, res, next);
        }

        return graphiqlHandler(req, res, next);
    };

    return expressMiddleware;
};