与蓝鸟的承诺异步异常处理 [英] Asynchronous exception handling with bluebird promises

问题描述

这是处理这种情况的最佳方式。我是在受控环境中，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);
    });

在从setTimeout的内扔，我们总是会得到：

When throwing from within the setTimeout we will always get:

$ node bluebird.js

c:\blp\rplus\bbcode\scratchboard\bluebird.js:6
                throw new Error("AJAJAJA");
                      ^
Error: AJAJAJA
    at null._onTimeout (c:\blp\rplus\bbcode\scratchboard\bluebird.js:6:23)
    at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)

如果发生掷然后setTimeout的蓝鸟捕前将它捡起来：

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!]

这是伟大的 - 但如何将一个手柄这种性质的节点或浏览器的流氓异步回调。

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

推荐答案

承诺不域，他们不会因异步回调例外。你不能做到这一点。

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

承诺也不过捕捉从内抛出的异常的然后 / 抓 / 无极构造回调。因此，使用

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<一个href=\"https://github.com/petkaantonov/bluebird/blob/master/API.md#promisedelaydynamic-value-int-ms---promise\"相对=nofollow> Promise.delay ），以获得所需的行为。从来没有在定制（非诺）异步回调抛出，始终拒绝周围的承诺。使用的try-catch ，如果它真正需要的。

(or just Promise.delay) to get the desired behaviour. Never throw in custom (non-promise) async callbacks, always reject the surrounding promise. Use try-catch if it really needs to be.

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