What i want to do is to read the property name of the request i send to my express.js server.Here is how i pass the json data to a post request.

document.querySelector('#checkout').onsubmit= async e =>{
    const form = new FormData(document.querySelector('#checkout'))
    let user = createUserInfo(form),
    

    order = {
       name: "Test_Name"
    }

    fetch("/checkout/create-order", {
        method: "POST",
        mode: "same-origin",
        redirect: 'manual',
        headers:{
            "Content-Type": "application/json"
        },
        body: JSON.stringify(
            {
                order: order,
                user: user
            }
        )
    }).then(res=>{
       res.ok
    }).then(data=>{
        console.log(data)
    })
}

And this is how i read it using express.js:

app.use(express.json())
const YOUR_DOMAIN = 'http://localhost:4242/checkout.html';

app.post('/checkout/create-order', async (req, res) => {
  console.log(req.body.order.name)
}

When i try to read the name property i get an error.

C:\xampp\htdocs\server.js:9
  console.log(req.body.order.name)
                             ^

TypeError: Cannot read properties of undefined (reading 'name')