返回pg-promise [英] Return in pg-promise

问题描述

我使用pg-promise模块为Node创建了一个包含所有查询的单独文件.虽然对于大多数查询，我只在查询后使用req, res，但对于一个查询，我想返回一个值.这没用.返回undefined.

I created a separate file with all my queries using pg-promise module for Node. While for most of them I just use req, res after a query, for one I want to return a value back. It does not work. It returns undefined.

passportLogin: (email)=> {
        db.one(`SELECT userid 
                FROM user`)
            .then( result => {
                return result;
            })
            .catch( error => {
                return error;
            });
    }

推荐答案

该代码同时存在两个问题:

That code has two problems at the same time:

• 无效的诺言使用，当在.catch中执行return result时，这不是处理诺言拒绝的方式，您必须提供错误处理或重新抛出/重新拒绝错误.
• pg-promise 库的无效使用.您使用方法一个，该方法应该在除根据该方法的文档，返回1条记录， ，并且同时您说的是I need to catch if it returns more than one row... ，这是一个逻辑矛盾.

• invalid promise use, when inside .catch you do return result, that's not how promise rejects are handled, you must either provide the error handling, or re-throw / re-reject the error.
• invalid use of pg-promise library. You use method one that's supposed to reject when anything other than 1 record is returned, as per the method's documentation, and at the same time you are saying I need to catch if it returns more than one row... , which is a logical contradiction.

其结果如下:您的查询成功执行，并返回多个记录，这反过来使方法

The result of it is as follows: your query executes successfully, and returns more than one record, which in turn makes method one reject, and then you take the rejection reason and turn it into a resolved one by doing return result. In all, your code is broken all over the place.

首先，对于 pg-promise ，您应该使用正确的方法，根据您希望返回的记录数，请参阅基础知识.

First, with pg-promise you are supposed to use the right method, according to the number of records you are expecting back, see The Basics.

然后根据您的业务逻辑处理.then/.catch.我在这里没有具体说明，因为您没有提供进一步的细节.

And then handle .then/.catch according to your business logic. I can't be more specific here, because you did not provide further details on this.

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