知识点汇总

[caoxinhui]

tip
源码实现
实现promise.retry

Promise.retry = function (fn, num) {
    function executeFn() {
        return new Promise((resolve, reject) => {
            resolve(fn())
        }).then(res => {
            return Promise.resolve(res)
        }).catch(e => {
            num--;
            if (num < 0) {
                return Promise.reject(e)
            } else {
                return executeFn()
            }
        })
    }
    return executeFn()
};

function getData() {
    let num = Math.floor((Math.random() * 10));
    return new Promise((resolve, reject) => {
        if (num === 1) {
            resolve(num)
        } else {
            reject(num)
        }
    })
}


Promise.retry(getData, 3).then(res => console.log(res)).catch(err => console.log('失败'));

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