How can i fetch a json and look for changes in that json

Question

Ok so what i'm planning do is: i want to fetch the json file from a server like an api, then search for changes since the last fetch and show me the changes.

So like: Fetch the json -> look for changes -> show me the changes

The json i like to fetch updates everyday a few times so i want that my output is up to date. It would be awesome if i can just fetch everytime the json updates like with js.watchfile.

So i tried to fetch the json that works. Also tried to loop the fetch and show me the response that also works

but i cant figured out how to look for the changes if the file is online

const fetch = require("node-fetch");
var url = 'https://example.com/jsondata'
function getDATA(resp){
    fetch(url)
    .then(function(data){
        return data.json();
    })
    .then(function(parsed){
        resp(parsed);
    }).catch(function(error){
        console.log('The error', error)
    })
}
function loop() {
    getDATA(function(resp){
        console.log(resp)
    })
}
setInterval(loop, 5000);