async与await执行顺序问题

async与await执行顺序问题

1. await仅能在被async修饰的函数中执行
2. 添加了await修饰的函数，默认异步任务执行完成之后才往下执行
3. 不加await默认返回一个promise对象，加了await会直接返回数据

举个例子

function resolveAfter1Seconds() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(‘resolved1‘);
    }, 5000);
  });
}
function resolveAfter2Seconds() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(‘resolved2‘);
    }, 10000);
  });
}

async function asyncCall() {
  console.log(‘calling‘);
      const result = await resolveAfter2Seconds();
  	console.log(result);//等待10秒后执行这句话
    console.log(‘calling‘);//接着执行这句话
    const result2 = await resolveAfter1Seconds();
  console.log(result2);//再等五秒后执行这句话
  // expected output: "resolved"
}

asyncCall();

async与await执行顺序问题

原文：https://www.cnblogs.com/attack204/p/14638615.html