Monitor a person's whatsapp online status. Use with whatsapp web.

stalk.js

const STATUS_SPAN_SELECTOR = '.O90ur'

function record(data)
{
    var a = [];
    // Parse the serialized data back into an aray of objects
    a = JSON.parse(localStorage.getItem('session') || '[]');
    // Push the new data (whether it be an object or anything else) onto the array
    a.push(data);
    // Alert the array value
    console.log(a);  // Should be something like [Object array]
    // Re-serialize the array back into a string and store it in localStorage
    localStorage.setItem('session', JSON.stringify(a));
}

// select the target node
var target = document.querySelector(STATUS_SPAN_SELECTOR);
console.log('recording from element', target)
 
// create an observer instance
var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
        record({time: new Date(), status: mutation.target.title})
    });
});
 
// configuration of the observer:
var config = { attributes: true, childList: true, characterData: true }
 
// pass in the target node, as well as the observer options
observer.observe(target, config);