Class Validator¶

Class-validator is a powerful validation library for TypeScript and JavaScript that allows you to use decorator and non-decorator based validation. It uses validator.js internally to perform validation and works on both browser and node.js platforms.

Key Features¶

Decorator and non-decorator based validation
Cross-platform compatibility (browser & node.js)
Works with TypeScript and JavaScript
Validates objects against classes
Validates arrays and nested objects
Custom validation decorators
Service container support
Rich set of built-in validators

Quick Example¶

import { validate } from 'class-validator';
import { Length, Contains, IsInt, Min, Max, IsEmail } from 'class-validator';

export class Post {
    @Length(10, 20)
    title: string;

    @Contains('hello')
    text: string;

    @IsInt()
    @Min(0)
    @Max(10)
    rating: number;

    @IsEmail()
    email: string;
}

let post = new Post();
post.title = 'Hello'; // too short
post.text = 'this is a great post about hell world'; // doesn't contain "hello"
post.rating = 11; // too high
post.email = 'google.com'; // not an email

validate(post).then(errors => {
    if (errors.length > 0) {
        console.log('validation failed. errors: ', errors);
    } else {
        console.log('validation succeed');
    }
});

Ready to get started? Head over to Installation.

Contributing¶

For information about how to contribute to this project, see TypeStack's general contribution guide.