sos-nextjs/api/middleware/validators.js

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

const validators = module.exports = {}

validators.validPassword = field => body(field).isString().isLength({min: 8, max: 100}).withMessage('Password must be at least 8 characters')

validators.bothPasswordsMatch = body('password').custom((pass, {req})=>{
  if(pass !== req.body.password2)
    throw new Error('Passwords do not match')
  return true
})

validators.validEmail = field => body(field).isString().isEmail()
  .withMessage('Email invalid')

validators.unusedEmail = field => validators.validEmail(field)
  .custom(async email=>{
    const user = await db.user.findByEmail(email)
    if(user) throw new Error('Email already in use')
  })

validators.validUrlSlug = field => body(field).isString().isLength({min: 3, max: 20}).matches(/^[-a-z0-9_]*$/i)
  .withMessage('Slug can be between 3-20 characters long, and can include letters, numbers, dash or underscore')

validators.requiredString = field => body(field).isString()
  .withMessage('Required')

validators.positiveInteger = field => body(field).isInt().custom(value => value > 0)
  .withMessage('Must be a positive integer')

validators.publishedBool = body('published').isBoolean()

validators.isUUID = field => body(field).isString().isUUID()

validators.address = [
  body('street1').isString().isLength({min: 1}).withMessage('Street address is required'),
  body('city').isString().isLength({min: 1}).withMessage('City is required'),
  body('state').isString().isLength({min: 1}).withMessage('State is required'),
  body('zip').isString().isLength({min: 1}).withMessage('Postal code is required')
]

validators.handleApiError = (req, res, next) => {
  const errors = validationResult(req)

  if(errors.isEmpty())
    return next()

  res.status(422).json({errors: errors.array()})
}