使用 bluebird 承诺的异步异常处理 [英] Asynchronous exception handling with bluebird promises

问题描述

处理这种情况的最佳方法是什么.我处于受控环境中，我不想崩溃.

What is the best way to handle this scenario. I am in a controlled environment and I don't want to crash.

var Promise = require('bluebird');

function getPromise(){
    return new Promise(function(done, reject){
        setTimeout(function(){
                throw new Error("AJAJAJA");
        }, 500);
    });
}

var p = getPromise();
    p.then(function(){
        console.log("Yay");
    }).error(function(e){
        console.log("Rejected",e);
    }).catch(Error, function(e){
        console.log("Error",e);
    }).catch(function(e){
        console.log("Unknown", e);
    });

当从 setTimeout 中抛出时，我们将始终得到:

When throwing from within the setTimeout we will always get:

$ node bluebird.js

c:lp
plusbcodescratchboardluebird.js:6
                throw new Error("AJAJAJA");
                      ^
Error: AJAJAJA
    at null._onTimeout (c:lp
plusbcodescratchboardluebird.js:6:23)
    at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)

如果抛出发生在 setTimeout 之前，那么 bluebirds catch 会捡起来:

If the throw occurs before the setTimeout then bluebirds catch will pick it up:

var Promise = require('bluebird');

function getPromise(){

    return new Promise(function(done, reject){
        throw new Error("Oh no!");
        setTimeout(function(){
            console.log("hihihihi")
        }, 500);
    });
}

var p = getPromise();
    p.then(function(){
        console.log("Yay");
    }).error(function(e){
        console.log("Rejected",e);
    }).catch(Error, function(e){
        console.log("Error",e);
    }).catch(function(e){
        console.log("Unknown", e);
    });

结果:

$ node bluebird.js
Error [Error: Oh no!]

这很棒 - 但是如何在节点或浏览器中处理这种性质的恶意异步回调.

Which is great - but how would one handle a rogue async callback of this nature in node or the browser.

推荐答案

Promises 不是 域a>，它们不会从异步回调中捕获异常.你不能那样做.

Promises are not domains, they will not catch exceptions from asynchronous callbacks. You just can't do that.

Promises 但是会捕获从 then/catch/Promise 构造函数回调中抛出的异常.所以用

Promises do however catch exceptions that are thrown from within a then / catch / Promise constructor callback. So use

function getPromise(){
    return new Promise(function(done, reject){
        setTimeout(done, 500);
    }).then(function() {
        console.log("hihihihi");
        throw new Error("Oh no!");
    });
}

(或只是 Promise.delay) 以获得所需的行为.永远不要抛出自定义(非承诺)异步回调，始终拒绝周围的承诺.如果确实需要，请使用 try-catch.

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