What are some examples of using class-validator in TypeScript?

Can you give me some examples of how to use class-validator in TypeScript?

Sure! Class-validator is a library that helps you validate TypeScript classes. For example, you can use decorators like @IsString() and @IsInt() to validate properties.

Can you show me a complete example with a class?

Absolutely! Here's a simple example:

import { IsString, IsInt, validate } from 'class-validator';

class User {
    @IsString()
    name: string;

    @IsInt()
    age: number;
}

const user = new User();
user.name = 'John';
user.age = 25;

validate(user).then(errors => {
    if (errors.length > 0) {
        console.log('Validation failed. Errors: ', errors);
    } else {
        console.log('Validation succeeded!');
    }
});

What happens if the validation fails?

If validation fails, the validate function returns an array of errors detailing what went wrong, which you can then handle accordingly.

Can I create custom validation decorators?

Yes, you can create custom validation decorators in class-validator. This allows you to define your own validation logic.