code: function uploadContent(client) {
    const content = document.getElementById('file-content').value.trim();
    const key = document.getElementById('object-key-content').value.trim() || 'object';
    console.log(`content => ${key}`);
  
    return client.put(key, new Buffer(content)).then(res => listFiles(client));
  }
docs: /* eslint no-unused-vars: [0]