@validup/express-validator

Wrap an express-validator chain as a validup Validator and run it inside a Container — without rewriting the chain.

npm install @validup/express-validator validup express-validator --save

Peer dependency	Supported versions
express-validator	^7.3.1

Quick start

import { Container, isValidupError } from 'validup';
import { createValidationChain, createValidator } from '@validup/express-validator';

const user = new Container<{ email: string; age: number }>();

user.mount('email', createValidator(() => createValidationChain().isEmail()));
user.mount('age',   createValidator(() => createValidationChain().isInt({ min: 0 })));

try {
    await user.run({ email: 'peter@example.com', age: 28 });
} catch (e) {
    if (isValidupError(e)) console.log(e.issues);
}

The adapter runs the chain as a ContextRunner against { body: ctx.value }, then translates the resulting ValidationError (field, alternative, alternative_grouped) into validup issues. Sanitizers in the chain (.toInt(), .trim(), …) carry through to the validup output.

createValidationChain()

createValidationChain() is a parameterless helper that returns express-validator's body() chain — pre-bound to read the value validup hands the validator. The chain is not keyed on the mount path; the field isolation is already done by the Container mount, so the chain just operates on the value as the entire body.

import { createValidationChain, createValidator } from '@validup/express-validator';

container.mount(
    'tags',
    createValidator(() => createValidationChain().isArray({ min: 1, max: 10 })),
);

Subclassing pattern

The dominant pattern is to subclass Container<T> and register chains inside initialize():

import { Container } from 'validup';
import { createValidationChain, createValidator } from '@validup/express-validator';

type User = { name: string; age: number; password: string };

class UserValidator extends Container<User> {
    protected override initialize() {
        super.initialize();

        this.mount('name', createValidator(() => createValidationChain()
            .exists()
            .notEmpty()
            .isLength({ min: 3, max: 128 })));

        this.mount('age', createValidator(() => createValidationChain()
            .isNumeric()
            .optional({ values: 'null' })));

        this.mount('password', createValidator(() => createValidationChain()
            .isLength({ min: 3, max: 128 })));
    }
}

Per-context chains

Pass a function to createValidator to switch chains based on the validator context (group, sibling values, ctx.context):

import { createValidationChain, createValidator } from '@validup/express-validator';

const tagsValidator = createValidator((ctx) => {
    const chain = createValidationChain().isArray({ min: 1, max: 10 });
    return ctx.group === 'optional' ? chain.optional({ values: 'null' }) : chain;
});

container.mount('tags', { group: 'required' }, tagsValidator);
container.mount('tags', { group: 'optional' }, tagsValidator);

API

Export	Description
createValidator(input)	Wrap a ContextRunner (or (ctx) => ContextRunner) as a validup Validator.
createValidationChain()	Return a fresh body() chain pre-bound for use with the adapter (parameterless).
buildIssuesForErrors(errors)	Convert an array of express-validator ValidationErrors into validup Issues.

function createValidator<C = unknown>(
    input: ContextRunner | ((ctx: ValidatorContext<C>) => ContextRunner),
): Validator<C>;

function createValidationChain(): ValidationChain;