简单的异步函数async/await例子

function resolveAfter2Seconds(x){
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(x)
    }, 2000)
  });
}

async function f1() {
  var x = await resolveAfter2Seconds(10);
  console.log(x)
}

f1()

来自慕课：https://www.imooc.com/video/16631