work/原生Promise_使用测试.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>原生Promise_使用测试</title>
</head>
<body>
<!--

<script type="text/javascript">
  // 创建promise对象
  const p = new Promise((resolve, reject) => { // 在Promise内部会同步执行executor函数
    console.log('executor()')
    // 1. 执行异步操作(比如发ajax请求, 启动定时器)
    setTimeout(() => {
      const time = Date.now() // 得到当前的时间: 如果是偶数代表成功, 否则代表失败
      // 2.1. 如果操作成功了, 调用resolve(value)来指定成功和成功的数据
      if(time%2 === 0) {
        resolve('成功的数据')  // 内部有没有直接: onResolved('成功的数据')
        console.log('resolve()之后')
      // 2.2. 如果操作失败了, 调用reject(reason)来指定失败及失败的原因
      } else {
        reject('失败的原因数据')
        console.log('reject()之后')
      }
    }, 1000)
  })
  console.log('new Promise()之后', p)

  p.then(
    value => {
      console.log('onResolved()', value)
    },
    reason => {
      console.log('onRejected()', reason)
    },
  )
  console.log('then()之后')

</script>
-->

<script type="text/javascript">
  /*new Promise((resolve, reject) => { // 在Promise内部会同步执行executor函数
    // resolve(1)  // 指定成功及成功的value
    reject(1) // 指定失败及失败的reason
    // throw 1 // 抛出异常
  }).then(
    value => {
      console.log('onResolved()', value)
      // return 2
      // throw 2
      // return Promise.resolve(2)
      return Promise.reject(2)
    },
    reason => {
      console.log('onRejected()', reason)
    },
  ).then(
    value => {
      console.log('onResolved()2', value)
    },
    reason => {
      console.log('onRejected()2', reason)
    }
  )*/

  const p1 = Promise.resolve(3)
  const p2 = Promise.resolve(Promise.resolve(5))
  const p3 = Promise.reject(6)

  Promise.all([p1, 'abc', p3, p2]).then(
    values => {
      console.log('onResolved()', values)
    },
    reason => {
      console.log('onRejected()', reason)
    }
  )
</script>

</body>
</html>