Middleware

A Validation object created with the Validation.profile() method can be used as a middleware function on the server side.

Syntax

Validation()(req, res, next)

// as Express middleware
app.post(url, Validation())

Parameters

Please refer to Express documentation.

Return value

None (undefined).

Exceptions

If invoked without having created a validation profile, throws the corresponding error. Also see “Exceptions” of the Validation().validate() method.

Description

When invoked on the server side, runs a data mapper function and the Validation().validate() method. Assigns a validation result to the incoming request object which can be accessed in the next executed middleware. Only validations created with the Validation.profile() method can be used as middleware functions.

Using a Validation object as a middleware function is intended to reduce boilerplate code.

Examples

import express from 'express';
import bodyParser from 'body-parser';

// validations created with the `Validation.profile()` method
import { signinV,  signupV } from 'your-validations-file-name.js';

const app = express();
const urlencodeParser = bodyParser.urlencoded({extended: false});

function signinRequestHandler(req, res) {
    const { validationResult } = req;

    if (validationResult.isValid) {
        // check credentials
        // ...
    }
    else {
        // respond with the validation error
        // ...
    }
}

function signupRequestHandler(req, res) {
    const { validationResult } = req;

    if (validationResult.isValid) {
        // create an account
        // ...
    }
    else {
        // respond with the validation error
        // ...
    }
}

// validations are added as middleware functions
app.post('/signin', urlencodeParser, signinV, signinRequestHandler);
app.post('/signup', urlencodeParser, signupV, signupRequestHandler);