demo with firebase

fetch("https://fir-6e9c1-default-rtdb.europe-west1.firebasedatabase.app/Books.json")
    .then((res) => {
        return res.json();
    })
    .then((response) => {
        for (const key in response) {
            console.log(response[key]);
        }
    })
    .catch(err => {
        console.error(err);
    })


fetch("https://fir-6e9c1-default-rtdb.europe-west1.firebasedatabase.app/Books.json", {
    method: "PUT",
    headers: {
        "Content-Type": "application/json"
    },
    body: JSON.stringify({
        Author: 'John Doe',
        'Books Genre': 'Scifi',
        Title: 'Demo book'
    })
})
    .then((res) => {
        if (res.ok) {
            console.log("PUT request was successful.");
        } else {
            console.error("PUT request failed.");
        }
    })
    .catch(err => {
        console.error(err);
    });