express validator node js code example

Example 1: express validator

// this method create custom express validator using middleware

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

exports.resultsValidator = (req) => {
  const messages = []
  if (!validationResult(req).isEmpty()) {
    const errors = validationResult(req).array()
    for (const i of errors) {
      messages.push(i)
    }
  }
  return messages
}

exports.registerValidator = () => {
  return [
    check('username')
      .notEmpty()
      .withMessage('username is required')
      .not()
      .custom((val) => /[^A-za-z0-9\s]/g.test(val))
      .withMessage('Username not use uniq characters'),
    check('password')
      .notEmpty()
      .withMessage('password is required')
      .isLength({ min: 8 })
      .withMessage('password must be 8 characters')
  ]
}

exports.loginValidator = () => {
  return [
    check('username').notEmpty().withMessage('username or email is required'),
    check('password').notEmpty().withMessage('password is required')
  ]
}

// how to use express validator in controller for results message
const errors = resultsValidator(req)
  if (errors.length > 0) {
    return res.status(400).json({
      method: req.method,
      status: res.statusCode,
      error: errors
    })
  }

// how to use express validator in route
route.post('/login', loginValidator(), (req, res) => {
   return res.status(200).send('Login Sucessfuly');
});

route.post('/register', registerValidator(), (req, res) => {
   return res.status(200).send('Register Sucessfuly');
});

Example 2: express validator

npm install --save express-validator

Example 3: express-validator

// ...rest of the initial code omitted for simplicity.
const { body, validationResult } = require('express-validator');

app.post('/user', [
  // username must be an email
  body('username').isEmail(),
  // password must be at least 5 chars long
  body('password').isLength({ min: 5 })
], (req, res) => {
  // Finds the validation errors in this request and wraps them in an object with handy functions
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(422).json({ errors: errors.array() });
  }

  User.create({
    username: req.body.username,
    password: req.body.password
  }).then(user => res.json(user));
});

Example 4: express validator

app.post('/form', [
  check('name').isLength({ min: 3 }),
  check('email').isEmail(),
  check('age').isNumeric()
], (req, res) => {
  const errors = validationResult(req)
  if (!errors.isEmpty()) {
    return res.status(422).json({ errors: errors.array() })
  }

  const name  = req.body.name
  const email = req.body.email
  const age   = req.body.age
})

Example 5: express validator

import { Request } from 'express'
import { check, validationResult, ValidationError, ValidationChain, Result, Meta } from 'express-validator'

export const expressValidator = (req: Request): ValidationError[] => {
	const errors: Result<ValidationError> = validationResult(req)

	const messages: ValidationError[] = []
	if (!errors.isEmpty()) {
		for (const i of errors.array()) {
			messages.push(i)
		}
	}
	return messages
}

export const registerValidator = (): ValidationChain[] => [
	check('firstName').notEmpty().withMessage('firstName is required'),
	check('firstName')
		.not()
		.custom((val: string) => /[^a-zA-Z]/gi.test(val))
		.withMessage('firstName cannot include unique character'),
	check('lastName').notEmpty().withMessage('lastName is required'),
	check('lastName')
		.not()
		.custom((val: string) => /[^a-zA-Z]/gi.test(val))
		.withMessage('lastName cannot include unique character'),
	check('email').notEmpty().withMessage('email is required'),
	check('email').isEmail().withMessage('email is not valid'),
	check('password').notEmpty().withMessage('password is required'),
	check('password').isLength({ min: 8 }).withMessage('password must be at least 8 characters'),
	check('location').notEmpty().withMessage('location is required'),
	check('location')
		.not()
		.custom((val: string) => /[^a-zA-Z]/gi.test(val))
		.withMessage('location cannot include unique character'),
	check('phone').notEmpty().withMessage('phone is required'),
	check('phone').isLength({ min: 10 }).withMessage('phone number must be at least 10 characters'),
	check('phone').isLength({ max: 12 }).withMessage('phone number must be at least 12 characters'),
	check('phone').isMobilePhone('id-ID').withMessage('phone number is not valid')
]

export const loginValidator = (): ValidationChain[] => [
	check('email').notEmpty().withMessage('email is required'),
	check('email').isEmail().withMessage('email is not valid'),
	check('password').notEmpty().withMessage('pasword is required')
]

export const emailValidator = (): ValidationChain[] => [
	check('email').notEmpty().withMessage('email is required'),
	check('email').isEmail().withMessage('email is not valid')
]

export const tokenValidator = (): ValidationChain[] => [
	check('token').notEmpty().withMessage('token is required'),
	check('token').isBase64().withMessage('token is not valid')
]

export const passwordValidator = (): ValidationChain[] => [
	check('password').notEmpty().withMessage('password is required'),
	check('password').isLength({ min: 8 }).withMessage('password must be at least 8 characters'),
	check('password')
		.not()
		.custom((value: string, { req }: Meta) => req.body.cpassword !== value)
		.withMessage('confirm password is not match with password'),
	check('cpassword').notEmpty().withMessage('cpassword is required'),
	check('cpassword').isLength({ min: 8 }).withMessage('cpassword must be at least 8 characters')
]