According to the doc you have to use findElements
with a s. If I modify a bit your XPath, you can have something like this :
const nodes = xpath.fromPageSource(html).findElements("//a[@class='classifiedTitle']");
console.log("Number of ads found:", nodes.length);
console.log("Link[0]:", nodes[0].getAttribute("href"));
console.log("Link[1]:", nodes[1].getAttribute("href"));
...
Of course it’s better if you write a loop to print all the links. Something like :
for (let x = 0; x < nodes.length; x++) {
console.log(nodes[x].getAttribute("href"));
}