x.js

let len = messages.length;
for (let i = 0; i < len; i++) {
    let min = i;
    for (let j = i + 1; j < len; j++) {
        if (messages[j].timestamp > messages[min].timestamp) {
            min = j;
        }
    }
    if (min !== i) {
        let tmp = messages[i];
        messages[i] = messages[min];
        messages[min] = tmp;
    }
}
return messages;