如何使用猫鼬检索多个集合

Question

因此，我尝试使用Mongoose检索多个文档，并使用HBS视图引擎呈现它们。 Unfortunatley，我知道如何渲染视图的唯一方法是在用于从MongoDB数据库中检索文档的find()函数的回调中调用res.render() 。 因此，我一次只能检索一个文档，并且我想知道如何将多个文档保存到变量中，然后使用res.render()进行渲染。 有人知道该怎么做吗？ 路由器代码如下。

基本上，我要从多个集合中提取数据，并且想知道如何将find()函数的输出另存为变量，然后将其传递给res.render()函数进行呈现。 您可以在下面看到我为将结果另存为变量而只返回一个承诺的尝试。

index.js：

var express = require('express');
var router = express.Router();
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/test');
var Schema = mongoose.Schema;
var moment = require('moment');

var supportForumListSchema = new Schema({
  title: String,
  description: String,
  numPosts: Number,
  dateCreated: Date
}, {collection: 'support-forum-listing'});

var artworkForumListSchema = new Schema({
  title: String,
  description: String,
  numPosts: Number,
  dateCreated: Date
}, {collection: 'artwork-forum-listing'});

var supportForumList = mongoose.model('supportForumList', supportForumListSchema);
var artworkForumList = mongoose.model('artworkForumList', artworkForumListSchema);

tempDate = new Date(1542325638042);
currentDate = new Date(1542333003752);
console.log("current date:" + currentDate.toDateString());
tempHoursAgo = currentDate - tempDate;
tempHoursAgo = tempHoursAgo / (1000*60*60);
tempDateString = tempHoursAgo.toFixed(0);   // could use Number(string) to convert back to number
console.log(tempDateString + "hours ago");

// temp new posts array
var newPosts = [
    {postTitle: "Need help!", numViews: 1, datePosted: tempDateString},
    {postTitle: "Unknown identifier", numViews: 0, datePosted: tempDateString},
    {postTitle: "Messing up my normals", numViews: 3, datePosted: tempDateString},
    {postTitle: "Anyone able to help?", numViews: 3, datePosted: tempDateString}
];

/* GET home page. */
router.get('/', function(req, res, next) {
    artworkDoc = artworkForumList.find().then(function(doc){
        return doc;
    });
    console.log(artworkDoc);
    supportForumList.find().then(function(supportDoc){
        res.render('index', { title: 'Home - 3D Artists Forum', headerTitle: "3D Artist Forums", supportForumList: supportDoc , artworkForumList: artworkDoc, latestPosts: newPosts});
    });
});

module.exports = router;

Answer 1

请记住，请求是异步调用，因此您应该先进行链接才能获得所需的结果，否则“ supportForumList.find（）”可能会在artworkForumList.find（）之前响应

试试这个

 router.get('/', function(req, res, next) { artworkDoc = artworkForumList.find().then(function(doc){ return doc; }).then( doc => { supportForumList.find().then(function(supportDoc){ res.render('index', { title: 'Home - 3D Artists Forum', headerTitle: "3D Artist Forums", supportForumList: supportDoc , artworkForumList: doc, latestPosts: newPosts}); });; }); 

在这种方法中，仅当artworkForumList.find（）已响应并且您在“ doc”变量中包含数据，然后将该数据作为参数传递时，才执行supportForumList.find（）。

希望能帮助到你