To to fix the Express.js ‘req.body undefined’ error, we can use the body-parser middleware to parse the POST form fields into a JavaScript object.
To install the package, we run:
npm install --save body-parser
Then we can write:
const express = require('express')
const app = express()
const port = 3000
const bodyParser = require('body-parser')
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: true
}));
app.post('/', (req, res) => {
res.json(req.body)
})
app.listen(port, () => {
console.log(`Example app listening to ${port}`)
})
to add body-parser into our app with:
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: true
}));
Now we can parse JSON or URL encoded request data into the req.body property.
Therefore, when we send request data into the POST / route, we see the request value returned as the response in an object.
