Choosing the best validation library for your JavaScript project can be confusing given the many options available. Each library has its strengths and ideal use cases, so it's crucial to understand what each offers to make an informed decision. In this article, we'll explore the top 5 validation libraries for JavaScript in 2024 with interactive examples to help you understand their usage and benefits.

1. Joi

Joi is a powerful and flexible validation library, widely used for server-side validation, particularly with Node.js. It allows you to create complex validation schemas for your data with ease.

import Joi from 'joi';

const schema = Joi.object({
  username: Joi.string().alphanum().min(3).max(30).required(),
  email: Joi.string().email({ minDomainSegments: 2 }).required(),
  password: Joi.string().pattern(new RegExp('^[a-zA-Z0-9]{3,30}$')).required(),
});

const { error, value } = schema.validate({ username: 'john_doe', email: 'john@example.com', password: 'mypassword123' });
if (error) {
  console.error('Validation error:', error.details);
} else {
  console.log('Valid data:', value);
}

2. Yup

Yup is popular for client-side validation, especially in React projects. It's commonly used with form management libraries like Formik.

import * as Yup from 'yup';

const schema = Yup.object().shape({
  username: Yup.string().min(3).max(30).required(),
  email: Yup.string().email().required(),
  password: Yup.string().min(8).required(),
});

schema
  .validate({ username: 'john_doe', email: 'john@example.com', password: 'mypassword123' })
  .then((value) => {
    console.log('Valid data:', value);
  })
  .catch((err) => {
    console.error('Validation error:', err.errors);
  });

3. Validator.js

Validator.js is a lightweight library that provides a comprehensive set of string validation and sanitization functions. It's perfect for simple validation tasks.

import validator from 'validator';

const email = 'john@example.com';
const isValidEmail = validator.isEmail(email);

console.log(`Is valid email: ${isValidEmail}`);

4. class-validator

class-validator is ideal for TypeScript and NestJS projects. It uses decorators to define validation rules on class properties.

import { validate, IsEmail, Length } from 'class-validator';

class User {
  @Length(3, 30)
  username: string;

  @IsEmail()
  email: string;

  @Length(8)
  password: string;
}

const user = new User();
user.username = 'john_doe';
user.email = 'john@example.com';
user.password = 'mypassword123';

validate(user).then((errors) => {
  if (errors.length > 0) {
    console.error('Validation errors:', errors);
  } else {
    console.log('Valid data:', user);
  }
});

5. Zod

Zod has seen a sharp rise in popularity, especially for TypeScript projects, due to its intuitive syntax and comprehensive type validation.

import { z } from 'zod';

const schema = z.object({
  username: z.string().min(3).max(30),
  email: z.string().email(),
  password: z.string().min(8),
});

try {
  const validData = schema.parse({ username: 'john_doe', email: 'john@example.com', password: 'mypassword123' });
  console.log('Valid data:', validData);
} catch (e) {
  console.error('Validation error:', e.errors);
}

Can We Use Zod with JS Projects Too?

Absolutely! While Zod is especially popular in TypeScript projects, it can be used in JavaScript projects as well. Its clear and concise API makes it a great choice for any JavaScript application needing robust validation.

const { z } = require('zod');

const schema = z.object({
  username: z.string().min(3).max(30),
  email: z.string().email(),
  password: z.string().min(8),
});

try {
  const validData = schema.parse({ username: 'john_doe', email: 'john@example.com', password: 'mypassword123' });
  console.log('Valid data:', validData);
} catch (e) {
  console.error('Validation error:', e.errors);
}

Popularity Trends Over the Last 5 Years

Here's a chart showing the popularity trends of these libraries over the past five years:

From the chart, it's evident that Zod has experienced the most significant growth, making it the best validation library for 2024, especially for TypeScript projects. Joi and Yup remain solid choices for server-side and client-side validation respectively. Validator.js continues to be useful for simple string validation, while class-validator is ideal for TypeScript and NestJS.

Conclusion

In 2024, the choice of the best validation library depends on your specific needs. Zod stands out for its rapid growth and TypeScript support. Joi and Yup are excellent for server-side and client-side validation. Validator.js is perfect for straightforward string validation, and class-validator is great for TypeScript and NestJS projects. Choose the library that best fits your project requirements and enjoy smoother, more reliable validation!