JSON serialization is a critical task in web development, particularly for applications built with Node.js and Express.js. While the native JSON serialization in Node.js (JSON.stringify()) is straightforward and convenient, it can become a performance bottleneck, especially under heavy load. This article introduces express-fast-json-stringify, a custom middleware package that leverages fast-json-stringify to significantly boost JSON serialization performance in Express applications.

What is fast-json-stringify?

fast-json-stringify is a JSON serialization library developed by the Fastify team. It enhances JSON conversion speed by analyzing JSON schema definitions and compiling them into highly optimized serialization functions. This makes it much faster than the native JSON.stringify(), particularly beneficial for high-performance applications.

Introducing express-fast-json-stringify

express-fast-json-stringify is an npm package that brings the performance benefits of fast-json-stringify to Express.js applications. By integrating this package, you can achieve faster JSON serialization, thus improving the overall performance of your application.

Installation

First, install the express-fast-json-stringify package:

npm install express-fast-json-stringify

Creating a JSON Schema

Define a schema object that specifies the structure of your JSON responses. This schema will be used by fast-json-stringify to optimize the serialization process.

import { Schema } from 'express-fast-json-stringify';

const schema: Schema = {
  title: 'Example Schema',
  type: 'object',
  properties: {
    firstName: { type: 'string' },
    lastName: { type: 'string' },
    age: {
      description: 'Age in years',
      type: 'integer',
    },
  },
};

Applying the Middleware

Use the fastJsonSchema middleware in your Express routes, passing the schema object as an argument. This will set up the optimized JSON serialization for that route.

import express, { Request, Response, NextFunction } from 'express';
import { fastJsonSchema, Schema } from 'express-fast-json-stringify';

const app = express();

const exampleSchema: Schema = {
  title: 'Example Schema',
  type: 'object',
  properties: {
    firstName: { type: 'string' },
    lastName: { type: 'string' },
    age: { type: 'integer' },
  },
};

app.get(
  '/',
  fastJsonSchema(exampleSchema),
  (req: Request, res: Response, next: NextFunction) => {},
);

Sending JSON Responses

Instead of using the default res.json() method, use the res.fastJson() method provided by the middleware to send JSON responses. This leverages the speed benefits of fast-json-stringify.

import { fastJsonSchema, Schema } from 'express-fast-json-stringify';

const schema: Schema = {
  title: 'Example Schema',
  type: 'object',
  properties: {
    firstName: { type: 'string' },
    lastName: { type: 'string' },
    age: {
      description: 'Age in years',
      type: 'integer',
    },
  },
};

app.get('/', fastJsonSchema(schema), (req, res, next) => {
  try {
    const data = {
      firstName: 'Simone',
      lastName: 'Nigro',
      age: 40,
    };
    res.fastJson(data);
  } catch (error) {
    next(error);
  }
});

Performance Benefits

Using express-fast-json-stringify offers several performance benefits:

1. Increased Speed: fast-json-stringify can serialize JSON data much faster than JSON.stringify(), especially for complex JSON objects.
2. Reduced CPU Usage: Faster serialization means less CPU time spent on processing, allowing your server to handle more concurrent requests.
3. Consistency and Validation: By defining JSON schemas, you ensure that the serialized data adheres to a predefined structure, improving data consistency and reducing the likelihood of errors.

Conclusion

Integrating express-fast-json-stringify into your Express.js application can provide substantial performance improvements, especially in scenarios where JSON serialization is a bottleneck. By leveraging the power of fast-json-stringify, you can achieve faster response times and handle higher loads, making your application more efficient and scalable.

To start using express-fast-json-stringify, follow the steps outlined in this article, and enjoy the benefits of faster JSON serialization in your Express applications. For a live demo, you can check out the StackBlitz demo.