Response.json is not a function

December 7, 2021

I need your help. I’m trying to learn how to execute a POST query to create a new object in a database using fetch. I use pure javascript. However, I get an error that looks like this:

Mistake TypeError: response.json is not a function at sendData (scrip4t.js:22) at HTMLButtonElement.onclick

What am I doing wrong? Thanks

HTML

<input type="text" id="name">
<input type="text" id="price">
<input type="text" id="description">
<button id="send" onclick="sendData()">submit</button>

const url = `http://localhost:8081/laptop`
let name = document.getElementById('name')
let price = document.getElementById('price')
let description = document.getElementById('description')

function sendData () {

let name_of_laptop = name.value
let price_of_laptop = price.value
let laptop_description = description.value

let data = {name: name_of_laptop, price: price_of_laptop, description: laptop_description}

try {
    const response = fetch(url, {
        method: 'POST',
        body: JSON.stringify(data),
        headers: {
            'Content-Type' : 'application/json'
        }
    });
    let json = response.json();
    console.log('Success', JSON.stringify(json))
} catch (error) {
    console.error('Mistake',error)
 }
}

>Solution :

You need to prefix them with await. Check here to understand async/await

...

async function sendData () {

...

try {
    const response = await fetch(url, {
        method: 'POST',
        body: JSON.stringify(data),
        headers: {
            'Content-Type' : 'application/json'
        }
    });

    let json = await response.json();
    console.log('Success', JSON.stringify(json))
} catch (error) {
    console.error('Mistake',error)
 }
}