How to reuse a custom validation chain as router.use(xxxValidator)

[convers39]

For example, I have a custom validator that consists of an array of validation:

const customValidator = (arg) => {
    const res = someLogic(arg)
    return res
}

const validateResult = (req, res, next) => {
    const errors = validationResult(req)
    if (!errors.isEmpty()) {
      res.status(400).json({ errors: errors.array() })
    } else {
      next()
    }
  }


export const validator = [
    query('xx').exists(),
    customValidator,
    validateResult
]

Now in my routers/routeA.js file, I want to apply this validation to all routes in this namespace like this:

import { validator } from 'xx/xx'

const router = Router()
router.use(validator)


router.get('/endpointA', controller.funcA)
router.get('/endpointB', controller.funcB)
//...

Instead of this:

import { validator } from 'xx/xx'

const router = Router()

router.get('/endpointA', validator, controller.funcA)
router.get('/endpointB', validator, controller.funcB)
//...

And of cause, this will not match the signature:

I understand it requires a RequestHandler to work, is there any workaround to apply a validation chain to multiple routes?

[gustavohenke]

Hey. Looks like a mismatch between express and express-validator. thanks for raising!

[gustavohenke]

Are you also able to come up with a small, contained replication repo?
It happens for me with this TS playground link:
https://www.typescriptlang.org/play?#code/JYWwDg9gTgLgBAUwB5iggzuuAzKERwDkyqG6hA3ALABQokscA3nAMYAWCrA1nAL448BYijSYAtADcAhgBtgAE2kxolWrVYQAdunjSwYOAF5EosgAoAlNRr6wAOgCu6BOY5du5wtggRCl63VbA3sAcwQYLwB6Hz8AGjZOHi9Y-2sgA

But it doesn't happen in any other environment, and I can't pinpoint the exact versions that cause the problem.

[convers39]

Sorry for the late reply

I made a simple example to reproduce here:

https://codesandbox.io/s/gallant-violet-e181qx?file=/src/index.ts

[gustavohenke]

Hey @convers39, I was taking a look at this, it seems all is fine?