express validator without express

express-validator is awesome, why just express!

I recently used express-validator in my express app and it was the best solution and now I am working on the front-end of that app with react. but I miss express-validator functionality in front-end for form validation.

I searched a lot on the net but I can’t find a way to implement it on my front-end is there a way? if there is no way so why keep this powerful thing on just express?

a separated library may be the solution

although I know that the express-validator uses validator.js under the hood but it can be very nice to have something like validation chains in the web apps something like :

import {createValidator} from 'the-name-for-separated-library'

const validator=createValidator([
    check('some-field')
    .exists()
    .isEmail().withMessage('invalid email')
]);

const validationResult=validator.validate({
    'some-field':'an invalid email'
});

if (!validationResult.isEmpty())
      showToEndUserSomeHow(validationResult.array({onlyFirstError:true}))

[chinesedfan]

If were familiar with how express middlewares run, you can reuse those APIs without changes in express-validator. I will show the main process and you can wrap them as a function as you wish. Not tested but should able to work.

const { body, validationResult } = require('express-validator')

// prepare an object
const req = {
  body: {} // put the data to be validated here
}

// prepare validators(middlewares)
const validators = [
  body('somefield1').isEmail(),
  body('somefield2').isEmail(),
]

// execute them and check the result 
Promise.all(
  // empty `res` and `next`
  validators.map(v => v(req, {}, () => {}))
).then(() => {
  const errors = validationResult(req)
})

[fedeci]

Closing this /cc @gustavohenke