Can't send data through axios and node back-end

Question

I am trying to access the expression passed from the backend to the frontend through axios.

Producer side:

const axios = require('axios');
const URL = "http://localhost:5000/"
let n1 = 3
let n2 = 5
let sum = n1+n2;



axios.post(URL, JSON.stringify({
    expression: sum,
  }))
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });

and on the consumer side:

const express = require('express')
const app = express()

app.post('/', (req, res) => {
  console.log(req.body);
})

app.listen(5000, () => console.log())

Ultimately, I would like to have the consumer side log "8"

At the moment, I have console.log(req) which gives me a large object. I would like to console.log(req.body) to return the value of the defined variable 'sum' — oobthenewb, Jun 30 '22 at 18:32
Maybe this is the answer you need https://stackoverflow.com/questions/10005939/how-do-i-consume-the-json-post-data-in-an-express-application — Yarin Levi, Jun 30 '22 at 18:43
On the client-side, I don't think the `JSON.stringify` method is necessary. Try to remove it. Document here: https://axios-http.com/docs/post_example — Đăng Khoa Đinh, Jul 01 '22 at 07:29

score 1 · Answer 1 · answered Jul 01 '22 at 07:31

1

You don't need to convert to JSON, axios serves JSON natively.

Add to the server:

app.use(express.json())

Just send you data:

axios.post(URL, { expression: sum, })
  .then(console.log)
  .catch(console.err)

answered Jul 01 '22 at 07:31

punund

4,321
3
34
45

Jared A Sutton · Answer 2 · 2022-06-30T18:43:54.560

0

From the "express" documentation:

req.body

Contains key-value pairs of data submitted in the request body. By default, it is undefined, and is populated when you use body-parsing middleware such as body-parser and multer.

Try including this before you try to register the endpoint:

const bodyParser = require('body-parser')

app.use(bodyParser.json())

You can also use express.json() and drop the 'body-parser' dependency:

// const bodyParser = require('body-parser')

app.use(express.json())

edited Jun 30 '22 at 18:43

answered Jun 30 '22 at 18:34

Jared A Sutton

369
3
8

Hey, I have tried this method, and I am getting ```{}``` this is a good start. I would like to return ```13``` – oobthenewb Jun 30 '22 at 19:14

score 0 · Answer 3 · answered Jul 01 '22 at 07:35

0

Axios have some security measures as well, you should put your IP address in const URL = "http://localhost:5000/"

answered Jul 01 '22 at 07:35

Naroto-Hasaka

49
4

Can't send data through axios and node back-end

3 Answers3