I am using npm module `[express-validator][1]` to validate my `query` and `body` parameter. As in express , we can pass list of function as a middleware , I have created an separate file as validator. Here my code of the validator..

`creditcard.validator.js`

```
const { check, body , query ,oneOf, validationResult } = require('express-validator/check');

exports.post_credit_check =  [
    function(req,res,next) { 
        body('firstName')
        .exists()
        .isAlphanumeric().withMessage('firstName should be alpanumeric')
        .isLength({min: 1 , max: 50}).withMessage('firstName should not be empty, should be more than one and less than 50 character')
        .trim();
        var errorValidation = validationResult(req);
        if ( errorValidation ) {
            return res.status(500).json({
                title: 'an error occured',
                error: errorValidation
            });
        }
        next()
    },

    function(req,res,next) {
    body('lastName')
    .exists()
    .isAlphanumeric().withMessage('lastName should be alpanumeric')
    .isLength({min: 1 , max: 50}).withMessage('lastName should not be empty, should be more than one and less than 50 character')
    .trim();
var errorValidation = validationResult(req);
            if ( errorValidation ) {
                return res.status(500).json({
                    title: 'an error occured',
                    error: errorValidation
                });
            }
            next()
        }
];

```

Here my the `route` file where I am passing the middleware validator array

```
var express = require('express');
var router = express.Router();
var Creditcard =  require('../models/creditcard.model');
const { validationResult } = require('express-validator/check');
var validate = require('../models/creditcard.validate');

router.post('/creditcarddetails', validate.post_credit_check , function(req, res, next) {
          .................
}

```

Though I am passing all middleware function in `validate.post_credit_check`, it not validating the body and not giving the error.