Promise returning undefined

Question

I am trying to use promise to send an ajax request to a php script which checks if a file exist on the server and returns a boolean value.

I have the below code but

Answer 1

You should return the promise, because you need to assign your result variable asynchronous.

function fileExists(url) {
  return new Promise(function(resolve, reject) {
    var xhr = new XMLHttpRequest();
    xhr.onload = function() {
        resolve(this.responseText);
    };
    xhr.onerror = reject;
    xhr.open('GET', url);
    xhr.send();
  });
}

fileExists("url_to_file").then(console.log);