promise.then()返回的新的promise结果状态由什么决定？

promise.then()返回的新的promise结果状态由什么决定？

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>promise的几个关键问题</title>
</head>
<body>
    <script>
        new Promise((resolve,reject) =>{
            resolve(2)
           
        }).then(
            value =>{
                console.log('onResolved1()'+value);
                
                // return 2
                // return Promise.resolve(22)
                // return Promise.reject(22)
                // throw 222

            },
            reason =>{
                console.log('onRejected1()'+reason);
            }
        ).then(
            value =>{
                console.log('onResolved2()'+value);
            },
            reason =>{
                console.log('onRejected2()'+reason);
            }
        )
    </script>
    
</body>
</html>

　　运行效果:

posted @ 2021-02-18 16:34  前端那点事  阅读(290)  评论(0)  编辑  收藏  举报