猫鼬承诺和Q承诺 [英] mongoose promise and Q promise

问题描述

[我会回答这个问题，但随时添加解决方案或其他可能发生的问题]

在使用q的诺言和猫鼬的nodejs项目上工作，我发现结合了两者的一些不直观的内容.

Working on a nodejs project where we use q promises heavily and mongoose I have found some unintuitive hickups combining the two.

第一个是猫鼬承诺没有.fail或.catch.

First one is that mongoose promise does not have .fail or .catch.

另一个是， Model.create 返回了一个承诺，该承诺调用了解决方法解析时使用多参数的函数.如果通过Q，则Q将仅使用第一个参数来调用resolve.

Another one is that Model.create returns a promise that calls the resolve function with mutliple arguments when resolved. If this goes through Q then Q will call the resolve with only the first argument.

请随时添加更多可能出现的问题；我将以解答方式解决这些问题.

Please feel free to add more problems that may occur; I will put how I solved these things in an answer.

推荐答案

您可以简单地使用

You can simply use the Q function to cast Mongoose promises to "proper" Q ones - this works in fact with every thenable.

所以只需使用

Q(someMongoosePromise) .then(…).catch(…);

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多个参数是一个不同的问题.但是，有一个非常简单的技巧:将它们转换为数组并使用该数组.

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Multiple arguments are a different problem. However, there is a very simple hack: convert them to an array and work with that.

Q(Model.create([doc1,doc2]).then(Array)) .spread(function(d1, d2){ … });

_{(此解决方案不适用于Model.create返回单个数字的承诺的情况)}

_{(This solution doesn't apply in case Model.create returns a promise for a single number)}

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