Promise rejects with await are not catches by the Middleware

Question

I'm using Nodejs.

I have a promise which request after a few seconds. But my Middleware not catches the error, but uncaughtException does.

router.all('/incaseoferror', async(req, res, next) => {

    const promise = await new Promise(function (resolve, reject) {
        setTimeout(function () {
            reject(new Error('this is a test err, the error-middleware NOT catch and it NOT OKAY'));
        }, 3000);
    });

  //  throw new Error('test error - the error-middleware catch it and that okay');
});

function clientErrorHandler(err, req, res, next) {

    console.log('in clientErrorHandler', err);
//but not catch the promise error!

});

process.on('uncaughtException', function (error) {

    // the error is catch here..
});

Here is the problem: Let's say I have login function from another library and it give me a promise. something has failed in the function, I cant catch the error in my error-middleware to give the user response that the request is failed.

I dont want to add try/catch in every middleware. (route===middleware)
I want use async/await
Using uncaughtException not help me because I can't return response to the user in the route.

So what can I do? any ideas?

Maybe it's time to switch from Express to Koa... – CedX Nov 26 '17 at 13:54 — CedX, Nov 26 '17 at 13:54

Rajkumar Somasundaram · Answer 1 · 2017-11-25T15:57:47.203

0

This should help you

await new Promise(function (resolve, reject) {
        setTimeout(function () {
            reject(new Error('this is a test err, the error-middleware NOT catch and it NOT OKAY'));
        }, 3000);
    })
.catch((err) => {
    clientErrorHandler(err);
 });

edited Nov 25 '17 at 15:57

answered Nov 25 '17 at 14:25

Rajkumar Somasundaram

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No. I Also want to use async/await. NOT Then/catch. – Shlomi Levi Nov 25 '17 at 15:01
I am using async/await to get the promise; You mean even for catching error you want to use async/await? – Rajkumar Somasundaram Nov 25 '17 at 15:02
No, I just expect to same behavior when I does `throw new Error` and the middleware catch. so for promise reject. – Shlomi Levi Nov 25 '17 at 15:07
So, even the first half of my answer doesnt satisfy your requirement. Am i right? – Rajkumar Somasundaram Nov 25 '17 at 15:36
@ShlomiLevi I have updated the answer. – Rajkumar Somasundaram Nov 25 '17 at 15:58

Promise rejects with await are not catches by the Middleware

1 Answers1