Question

我尝试使用bluebird进行Promisify Mongoose连接，我需要减少回调，所以我使用了bluebird.But它给了我下面的错误。

var expect = require('chai').expect;
var mongoose = require('mongoose');

var jobModel = require('../models/job');

var Promise = require('bluebird');

function resetJobs() {
  return new Promise(function(resolve, reject) {
    mongoose.connection.collections['jobs'].drop(resolve, reject);
  });
};

function findJobs(query) {
  return Promise.cast(mongoose.model('Job').find({}).exec());
};

var connectDB = Promise.promisify(mongoose.connect,mongoose);
describe('get jobs', function() {
  it('Should not be empty since jobs are seeded', function(done) {
    connectDB('mongodb://localhost/jobfinder').then(function() {
      resetJobs()
        .then(jobModel.seedJobs)
        .then(findJobs).then(function(jobList) {
          expect(jobList.length).to.be.at.least(1);
          done();
        });
    });
  });
});

但这给了我一个错误

Unhandled rejection TypeError: Cannot read property 'connection' of undefined
at Mongoose.connect (F:\MyProjects\JobFinder\node_modules\mongoose\lib\index.js:232:18)
at tryCatcher (F:\MyProjects\JobFinder\node_modules\bluebird\js\release\util.js:11:23)
at ret (eval at <anonymous> (F:\MyProjects\JobFinder\node_modules\bluebird\js\release\promisify.js:184:12), <anonymous>:14:23)
at Context.<anonymous> (F:\MyProjects\JobFinder\test\jobs-data-spec.js:22:3)

我正在使用的软件包版本如下

"bluebird": "^3.1.1",
"express": "^4.13.4",
"mongoose": "^4.3.6"

Answer 1

我正在制作相同的教程 Bluebird改变了3.0中的api // 2.x Promise.promisify（fn，ctx）; // 3.0 Promise.promisify（fn，{context：ctx}）;

我更改了呼叫，并且呼叫停止抛出错误。

点击此处查看Bluebird说明： http://bluebirdjs.com/docs/new-in-bluebird-3.html

希望这有帮助

Answer 2

以下代码似乎对我有用。

var connectMongoose = Promise.promisify(mongoose.connect, {context: mongoose}); 
connectMongoose('MONGO_URL', mongoose)
 .then(..)

Answer 3

我也在制作同一个教程，这就是我为解决这个问题所做的工作。

npm uninstall bluebird
npm install --save bluebird@2.0

然后当您使用mocha运行测试时，您应该通过。

Answer 4

你也可以手动promisify mongoose.connect，而不使用bluebird：

const mongoose = require('mongoose');
const { promisify } = require('util');


const connectMongoose = promisify((resolve, reject) => {
    const options = { useNewUrlParser: true, useUnifiedTopology: true };
    const uri = 'mongodb+srv://<USERNAME>:<PASSWORD>' +
        '@cluster0.iz4o8.mongodb.net/<DB-NAME>?retryWrites=true&w=majority';
    try {
        mongoose.connect(uri, options, resolve);
    } catch (err) {
        reject(err);
    }
});


(async () => {
    try {
        await connectMongoose();
        console.log('connected to monoose! :)');
    }
    catch (err) {
        console.error('could not connect to mongoose :(', err);
        process.exit(-1);
    }
})();

在Promisifying Mongoose Connect中输入错误

4 个答案: