read all function

function readAll() {
  let objectStore = db.transaction("name").objectStore("name");
  let users = [];

  objectStore.openCursor().onsuccess = function(event) {
    let cursor = event.target.result;

    if (cursor) {
      users.push(cursor.value.name);
      cursor.continue();
    } else {
      self.postMessage('Every users: ' + users.join(', '));
    }
  };
}