如何将此PHP curl命令转换为JS

var xhr = new XMLHttpRequest();
xhr.open("GET", "https://api.example.com/data", true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    var response = JSON.parse(xhr.responseText);
    // 处理响应数据
  }
};
xhr.send();

fetch("https://api.example.com/data", {
  method: "GET",
  headers: {
    "Content-Type": "application/json"
  }
})
.then(function(response) {
  if (response.ok) {
    return response.json();
  } else {
    throw new Error("请求失败");
  }
})
.then(function(data) {
  // 处理响应数据
})
.catch(function(error) {
  console.log(error);
});