A few months ago, I began working on a personal project that involved client-server communication. To take advantage of this, I tried using GraphQL. While I generally liked the approach of having a single API endpoint and resolvers, the overhead of setting up and maintaining a GraphQL server was too much for a one-person operation like mine. That's when I came up with the idea of replacing GraphQL with a more lightweight and easier-to-manage approach. My solution, which I'll describe in more detail below, has proven to be a game-changer for me and has significantly improved my efficiency and speed of development. Unlike GraphQL, my solution does not require the overhead of setting up and maintaining multiple schemas which need to be set for the client and server. Instead, it defines resolver functions to provide flexible alternative. In this article, I'll walk you through the details of my solution and the benefits it has brought to my pet project." Step 1 - Creating Basic Express App At the beginning let's define a basic expressjs application which will have a single endpoint. app.js import express from 'express';
import apiRouter from "./api-route.js";
import cors from "cors";

const app = express();
app.use(express.json());
app.use('/api', apiRouter);
app.use('cors');
const port = process.env.PORT || 5000;
const server = app.listen(port, () => {
    console.log(`Listening to port ${port}`);
}); and api-route.js import express from "express";
const router = express.Router();

router.get('*', async (req, res, next) => {
    const response = {
        text: 'Hello World!'
    };
    return res.json(response);
})

export default router; This is simplest express app possible, every GET request to localhost:5000/api/* will be responded with body: {
  "text": "Hello World"
} You can find this code at the following GitHub repository in branch : step-1 anatoly314/server-boilerplate-article Step 2 - A Better Approach to API Development: Resolvers Provider To add more endpoints to our app, we could follow the traditional approach of grouping all the endpoints into route files and importing them one by one. However, I'd like to suggest a new way that simplifies this process. Instead, we can create an folder and define a new file within it called , which will contain the following content: api resolvers-provider.js resolvers-provider.js import glob from 'glob';

const __registeredResolvers = {};

export const registerResolver = (resolverName, resolver) => {
    if (__registeredResolvers[resolverName]) {
        throw new Error(`Resolver with ${resolverName} name already exists`);
    }
    __registeredResolvers[resolverName] = resolver;
}

export const getResolver = resolverName => {
    const resolver = __registeredResolvers[resolverName];
    if (!resolver) {
        throw new Error(`Resolver with ${resolverName} wasn't registered`);
    }
    return resolver;
}

export const registerResolvers = async directoryName => {
    const files = glob.sync(directoryName + '/**/*.js', {
        absolute: true
    });
    const resolverFiles = files.filter(file => file.endsWith('-resolvers.js'));
    for (const resolverFile of resolverFiles) {
        const module = await import(resolverFile);
        Object.keys(module).forEach(key => {
            const resolver = module[key];
            registerResolver(resolver);
        })
    }
} To invoke , simply add the following code to your file:" resolver-provider.js api-route.js ...
const __dirname = dirname(fileURLToPath(import.meta.url));
await registerResolvers(__dirname);
... When you invoke , it will search for all files that end with within the directory and its subdirectories. registerResolver -resolvers.js api It will then register all of the exported functions from those files as resolvers. Next, add a new file called to the directory, and include the following content: users-resolvers.js api/users users-resolvers.js export const getUsersByName = ({body}) => {
    const {name} = body;
    const allUsers = [{
        id: 1,
        name: 'Anatoly',
        age: 42
    }, {
        id: 2,
        name: 'Yulia',
        age: 34
    }, {
        id: 3,
        name: 'John',
        age: 55
    }];

    const filteredUsers = allUsers.filter(user => user.name === name);
    return filteredUsers;
} When you run your server, all exported functions from files that match the pattern will automatically be registered as resolvers. api/*-resolvers.js To use the registered resolvers, there's one last step we need to take. We need to replace the existing GET endpoint in with the following POST endpoint: api-route.js router.post('*', async (req, res, next) => {
    try {
        const body = req.body;
        const authorizedUser = req.header('Authorization');
        const resolverName = req.url.substring(1);
        const resolver = getResolver(resolverName);
        const result = await resolver({body, authorizedUser});
        return res.json(result);
    } catch (err) {
        if (err.message === 'Unauthenticated') {
            res.status(401);
            res.send(err.message);
        } else {
            res.status(500);
            res.send("Server error");
        }
    }
}); To invoke our resolver, we can make a POST request to the following URL template: . localhost:5000/api/<RESOLVER_NAME> For example, to invoke the resolver, we would make a request to . The body of the request should contain
the necessary input data for the resolver to process. getUsersByName localhost:5000/api/getUsersByName {
    "name": "Anatoly"
} When our server receives this request, it will invoke the resolver
with the name that's defined in the file
located in the directory. getUsersByName users-resolvers.js api/users The contents of the body will be passed to the resolver as input. So what have we gained from this approach? Although there was some effort required at the beginning to set up the resolvers provider, the benefits are significant. Now, if we need to add another endpoint, instead of defining the entire endpoint code in the old way, we can simply add a new function to the existing resolvers provider or create a new resolvers provider. This results in less code, fewer bugs, and less time spent on development overall. Step 3 - Secure Your Resolvers with JavaScript Decorators With the boilerplate we've created, we've replaced the traditional ExpressJS API endpoints with a Resolvers approach that simplifies our codebase and makes developers' lives much easier. However, this approach lacks middleware support, which means we need to find an alternative way to handle tasks like authentication and authorization that would normally be done with middleware. One option is to use JavaScript decorators. We will create a JavaScript decorator that requires authentication for requests to a resolver. One possible implementation is to check that the header of the request contains the word . Authentication admin Javascript Decorators considered safe to use now that they're at stage 3 Stage 3 is the "Candidate" stage. At this stage, the proposal has been accepted by TC39 as a potential addition to the language and has been approved for inclusion in a future ECMAScript version. The proposal is considered mostly complete and has been reviewed and refined by TC39 members, but it may still undergo some changes based on feedback from implementers and developers. Proposals at Stage 3 are generally considered safe to use and are available in some experimental JavaScript runtimes, but they are not yet officially part of the language. For more details look here: tc39/proposal-decorators Since JavaScript decorators are still considered an experimental feature and Node.js currently does not have built-in support for them, we will need to use Babel to transpile our code. To do this, we will create a file in the root of our project, which will allow us to configure Babel and use its transpiling capabilities: .babelrc {
  "presets": [
    [
      "@babel/preset-env",
      {
        "modules": false
      }
    ]
  ],
  "env": {
    "development": {
      "sourceMaps": "inline",
      "retainLines": true
    }
  },
  "plugins": [
    "@babel/plugin-syntax-top-level-await",
    ["@babel/plugin-proposal-decorators", {
      "version": "2022-03"
    }]
  ]
} To implement the necessary changes, you should first include the code block below in the script section of your file: package.json {
    "build": "babel src -d dist",
    "start": "npm run build && node dist/app.js",
    "start-nodemon": "nodemon --watch './src/**/*.js' --exec npm run start"
} Then, execute the following command to install the required : devDependencies npm install --save-dev @babel/core @babel/cli @babel/preset-env @babel/plugin-proposal-decorators Once this is done, you can start the app by running . npm run start-nodemon Babel will transpile the code in the folder to a new folder, execute it, and automatically recompile it upon any changes made to the project. Before we can start using JavaScript decorators, we need to make some changes to our code. Specifically, the following files need to be modified: and src dist src/api/users/users-resolvers.js src/api/resolvers-provider.js As per the , decorators can be used with Classes and their elements such as fields, methods, and accessors. To leverage this feature, we need to ensure that our resolvers provider is an instance of a Class. Therefore, we will modify the code in to the following: proposal src/api/users/users-resolvers.js class UsersResolvers {
    getUsersByName ({body}) {
        const {name} = body;
        const allUsers = [{
            id: 1,
            name: 'Anatoly',
            age: 42
        }, {
            id: 2,
            name: 'Yulia',
            age: 34
        }, {
            id: 3,
            name: 'John',
            age: 55
        }];

        const filteredUsers = allUsers.filter(user => user.name === name);
        return filteredUsers;
    }
}

export default UsersResolvers; We also need to make changes to our to allow it to create instances of a class and retrieve references to its class methods: src/api/resolvers-provider.js ...
for (const resolverFile of resolverFiles) {
    const module = await import(resolverFile);
    const instantiatedResolver = new module.default();
    Object.getOwnPropertyNames(module.default.prototype).forEach(key => {
        if (key !== 'constructor') {
            const resolver = instantiatedResolver[key];
            registerResolver(key, resolver.bind(instantiatedResolver.self));
        }
    })
}
... Now that all the preparations have been completed, we can start writing our first JavaScript decorator. Let's create a new folder called and add a file to it
called : src/decorators auth-decorator.js auth-decorator.js export function authRequired(userType){
    return function (value, { kind, name }) {
        if (kind === "method" || kind === "getter" || kind === "setter") {
            return function (...args) {
                const {authorizedUser} = args[0];
                if (authorizedUser !== userType) {
                    throw new Error("Unauthenticated");
                }
                const ret = value.call(this, ...args);
                return ret;
            };
        }
    }
} And we can apply it to the method in as follows: getUsersByName users-resolvers.js ...
@authRequired("admin")
getUsersByName ({body}) {
 ...
}
... By adding the decorator to a resolver function, such as in , requests to that resolver will require authentication. This means that the request must contain a value of in the header, or else the request will be
rejected with a error indicating that it is unauthenticated. authRequired getUsersByName users-resolvers.js admin Authentication 401 This is just a basic example of what can be done with decorators. In general, anything that can be achieved with middleware can be achieved with decorators, offering great flexibility in the way you handle requests in your application. Step 4 - Creating React Hook which will seamlessly invoke resolvers We have implemented server side approach which replaces regular API with endpoints by approach with resolvers, let's create ReactJS hook which will call to these resolvers seamlessly: import axios from "axios";
import {useState} from "react";

const RESOLVER_API_URL = "http://localhost:4000/api";

export const useResolver = (resolverName) => {
    const [result, setResult] = useState(null);
    const [loading, setLoading] = useState(null);

    const invokeResolver = async data => {
        setLoading(true);
        try {
            const url = `${RESOLVER_API_URL}/${resolverName}`;
            const config = {
                url,
                headers: {
                    Authorization: 'admin'
                },
                method: 'POST',
                data: data
            }
            const response = await axios(config);
            setResult(response.data);
            return response.data;
        } catch (err) {
            const errText = `Error invoking resolver ${resolverName}`;
            console.log(errText, err);
            throw new Error(errText);
        } finally {
            setLoading(false);
        }
    }

    return [invokeResolver, result, loading];
} A call to any resolver can now be as simple as the following: const [getUsersByName, users, loadingUsers] = useResolver("getUsersByName"); The function can now be called using a simple syntax. getUsersByName The results of the invocation are stored in the property, while the boolean flag indicates the current invocation state. users loadingUsers Here's the complete example of a React component that uses this hook: import React, {useState} from "react";
import {useResolver} from "../../resolvers/resolvers-hook";

const Users = () => {

    const [getUsersByName, users, loadingUsers] = useResolver("getUsersByName");
    const [inputValue, setInputValue] = useState('');
    const handleInputChange = (event) => {
        setInputValue(event.target.value);
    }

    return (
        <div>
            {
                loadingUsers && <div>LOADING</div>
            }
            Users with the name:
            <input
                type="text"
                value={inputValue}
                onChange={handleInputChange}
            />
            <button onClick={() => getUsersByName({
                name: inputValue
            })}>Load Users</button>
            <pre>
                {JSON.stringify(users, null, 2)}
            </pre>
        </div>
    )
}

export default Users; Credits: ChatGPT, I would like to express my gratitude to for the incredible help provided to me. The chatbot was instrumental in guiding me through various questions and tasks, and helped me to improve my English writing skills. The examples and explanations given were invaluable in understanding complex concepts. I would like to thank for creating such an amazing resource. ChatGPT the entire team behind ChatGPT GraphQL developer community, I would like to acknowledge the contributions of the , including and . Much of what I have accomplished in this project has been inspired by their codebase." GraphQL developer community Facebook Apollo

The Lightweight Alternative to GraphQL, Resolvers Instead of Endpoints

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