无法从完成处理程序中取回数组

function processData(callback) {
  // 异步操作
  setTimeout(function() {
    const result = [1, 2, 3];
    callback(result);
  }, 1000);
}

processData(function(result) {
  console.log(result); // [1, 2, 3]
});

function processData() {
  return new Promise(function(resolve, reject) {
    // 异步操作
    setTimeout(function() {
      const result = [1, 2, 3];
      resolve(result);
    }, 1000);
  });
}

processData().then(function(result) {
  console.log(result); // [1, 2, 3]
});

async function processData() {
  return new Promise(function(resolve, reject) {
    // 异步操作
    setTimeout(function() {
      const result = [1, 2, 3];
      resolve(result);
    }, 1000);
  });
}

async function main() {
  const result = await processData();
  console.log(result); // [1, 2, 3]
}

main();