如何在JavaScript中同步加载JSON？

function loadJSONSync(url) {
  var request = new XMLHttpRequest();
  request.open('GET', url, false);
  request.send(null);
  if (request.status === 200) {
    return JSON.parse(request.responseText);
  } else {
    throw new Error('Failed to load JSON file');
  }
}

// 调用示例
var data = loadJSONSync('data.json');
console.log(data);

function loadJSONSync(url) {
  return fetch(url)
    .then(function(response) {
      if (response.ok) {
        return response.json();
      } else {
        throw new Error('Failed to load JSON file');
      }
    })
    .then(function(data) {
      return data;
    })
    .catch(function(error) {
      console.log(error);
    });
}

// 调用示例
loadJSONSync('data.json')
  .then(function(data) {
    console.log(data);
  });