等待react中的函数

async function fetchData() {
  const response = await fetch('https://api.example.com/data');
  const data = await response.json();
  // 处理数据
}

function fetchData() {
  return new Promise((resolve, reject) => {
    fetch('https://api.example.com/data')
      .then(response => response.json())
      .then(data => {
        // 处理数据
        resolve(data);
      })
      .catch(error => {
        reject(error);
      });
  });
}

function fetchData(callback) {
  fetch('https://api.example.com/data')
    .then(response => response.json())
    .then(data => {
      // 处理数据
      callback(data);
    })
    .catch(error => {
      // 处理错误
      callback(null, error);
    });
}