一個promise指定多個成功/失敗的回調函數.都會調用？
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<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>promise幾個關鍵問題</title>
</head>
<body>
<script>
/* 1、如何改變promise的狀態
(1)resolve(value) :如果當前的狀態是pendding就會變成resolved
(2)resolve(reason)) :如果當前的狀態是pendding就會變成rejected
(3)拋出異常:如果當前的狀態是pendding就會變成rejected
2.一個promise指定多個成功/失敗的回調函數.都會調用？
當promise狀態改變時都會調用
*/
let p = new Promise((resolve,reject) =>{
// resolve('成功')
reject('失敗')
// throw '122'
})
// p.then((value) =>{console.log(value)}).catch(reason =>{
// console.log(reason);
// })
p.then(
(value) =>{console.log(value)},
(reason) =>{
console.log('reason'+reason);
})
p.then(
(value) =>{console.log(value)},
(reason) =>{
console.log('reason2'+reason);
})
</script>
</body>
</html>
