MongoDB:cursor.toArray返回Promise {< pending> } [英] MongoDB: cursor.toArray returns Promise { <pending> }

问题描述

我写了一个查询:

var results = db.collection('diseases').find({
  'ttl.txt': {
    $regex: data,
    $options: 'i'
  }
}).toArray();

问题

然后我将results打印到控制台.

Problem

Then I printed results to a console.

if (results.length > 0) {
  console.log(results);
}

ToArray方法必须返回找到的文档的数组.但是此方法向我返回了以下字符串:Promise { <pending> }.

ToArray method must return array of found documents. But this method returns me this string: Promise { <pending> }.

如何返回找到的文档数组而不是此字符串?

How can I return array of found documents instead of this string?

toArray:链接到文档

推荐答案

您会收到此错误，因为find()方法是异步的，这就是诺言未决的原因:它仍在获取.

You are getting this error because the find() method is asynchronous, that's why the promise is pending: it is still fetching.

db.collection('diseases').find({
  'ttl.txt': {
    $regex: data,
    $options: 'i'
  }
}).toArray().then((data) => {
    // Here you can do something with your data
    doSomethingWithTheResult(result)
})

请注意，您的数据包含在回调中.有关承诺的更多信息，请检查承诺

Notice that you have your data inside a callback. For more info about promises check Promise

根据您的节点版本(我认为是7.6+)，您可以使用类似的

Depending on your node version (7.6+ I believe), you can use something like this

async function getResults() {
    return db.collection('diseases').find({
        'ttl.txt': {
        $regex: data,
        $options: 'i'
        }
    }).toArray();
}

const results = await getResults();

因此，您的代码看起来像是同步代码.关键是等待诺言结果的async/await命令.

So your code with look like a synchronous code. The key here is the async/await command that wait for the promise results.

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