Express-Validator v4 minimalistic example always return error

Question

I can't get this very basic piece of code to work in the new version. Here is my code

const express = require("express");
const bodyParser = require("body-parser");
const validator = require("express-validator");
const { check, validationResult } = require("express-validator/check");

    const app = express(); 
    app.use(bodyParser.json());
    app.use(validator());

    app.post('/',
             [ check("email").isEmail() ],
             (req, resp) => { 
                const errors = validationResult(req);
                resp.send(errors.mapped()); });
    
app.listen(3000, () => { console.log('listening on port 3000'); });

I send a post request with body containing :

{ "email": "ha@gmail.com" }

The Response is ALWAYS an error even if the email I give is perfectly correct

{ "email": { "location": "body", "param": "email", "msg": "Invalid value" } }

Am i missing something ?

Answer 1

That's because req.body.email is always undefined, you have to tell body-parser middleware to parse incoming request bodies into object by adding this line:

app.use(bodyParser.urlencoded({ extended: true }));

One other thing, always use errors.isEmpty() to check whether the validation contains errors or not:

app.post('/send', [ check("email").isEmail() ], (req, resp) => { 

    console.log(req.body);

    const errors = validationResult(req);

    if (!errors.isEmpty()) {
        return resp.send(errors.mapped()); 
    }

    resp.send('no errors');

});