detecting 3rr on wikipedia using the selected revisions

3rr.js

var checked_revs = document.querySelectorAll('#pagehistory input[type=checkbox]:checked');
var user_revs = {};
var user, parent, date, revs;
checked_revs.forEach(function(check){
    parent = check.parentNode;
    user = parent.querySelector('.mw-userlink').innerText;
    date = new Date(parent.querySelector('.mw-changeslist-date').innerText);
    rev = {"date": date, "parent": parent};
    revs = user_revs[user];
    if (!revs) {
        user_revs[user] = [rev];
    } else if (revs.length < 4) {
        revs = user_revs[user] = revs.filter(r => (r.date - date) < 24*3600*1000);
        revs.push(rev);
    }
});


var colors = ["DodgerBlue", "OrangeRed", "Crimson", "DarkGoldenRod", "HotPink", "Yellow", "Red"];
for ([user, revs] of Object.entries(user_revs)) {
    if (revs.length == 4) {
        var color = colors.pop();
        var msg = `[[user:${user}|${user}]] has violated 3RR in: \n`;
        revs.forEach(function(rev){
            rev.parent.style.background = color;
            href = rev.parent.querySelector('.mw-history-histlinks span:nth-last-child(1) a').href;
            msg += `[${href}]`;
        });
        console.log(msg);
    }
}