Question

如何处理连接错误5次并创建异常？

    try {
        await sqlConnection()
    }
    catch (e) {
        console.log(e);
    }

Answer 1

如果您只是在发生任何错误时尝试重试5次，然后在5次错误后失败并显示错误，并且sqlConnection()返回成功时解析的承诺并在出现错误时拒绝，则可以执行像这样的东西：

function delay(t) {
    return new Promise(resolve => {
        setTimeout(resolve, t)
    })
}

function connect(retries = 5, pauseTime = 100) {
    let cntr = 0;

    function run() {
        ++cntr;
        return sqlConnection().catch(err => {
            console.log(err);
            if (cntr < retries) {
                return delay(pauseTime).then(run);
            } else {
                // let promise reject
                throw err;
            }
        });
    }
    return run();
}

connect(5, 100).then(db => {
   // connected here
}).catch(err => {
   // failed to connect here
});

Answer 2

只需使用循环：

for (let tries = 5; true; tries--) {
    try {
        await sqlConnection()
        break; // a `return` works even better
    } catch (e) {
        console.log(e);
        if (tries < 0)
            throw e;
    }
}

如何处理5次连接错误并创建异常？

2 个答案: