[js] 写一个方法实现promise失败后自动重试

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>

</body>

</html>
<script>
    Promise.retry = (fun, limit = 5) => {
        return new Promise((resolve, reject) => {
            let __num = 1;
            let __run = () => {
                fun()
                    .then(res => {
                        resolve(res);
                    })
                    .catch(err => {
                        if (__num++ >= limit) {
                            reject(err)
                        } else {
                            console.log('retry again!!')
                            __run()
                        }
                    })
            }
            __run()
        })
    }

    let k = 0

    function test() {
        return new Promise((resolve, reject) => {
            if (++k >= 3) {
                resolve(k)
            } else {
                reject('hhh')
            }
        })
    }

    Promise.retry(test).then(res => {
            console.log('resolve: ', res)
        }).catch(err => {
            console.log('reject: ', err)
        })
        // retry again!!
        // retry again!!
        // resolve: 3
</script>

运行结果
在这里插入图片描述

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