promise

https://blog.csdn.net/qq_34645412/article/details/81170576

https://segmentfault.com/a/1190000007463101#articleHeader2

// 创建一个新的promise对象
const p=new Promise((resolve, reject) => {
  console.log('excutor'); //执行器函数同步进行
  // 执行异步任务
  setTimeout(() => {
    let time = Date.now()
    //偶数代表异步成功
    if (!(time % 2)) {
      resolve(`success data ${time}`)
    } else {
      reject(`error data ${time}`)
    }
  }, 1000);

}).then(data => console.log(data)).catch(e => console.log(e))
//onResolved onRejected