类型错误：无法使用猫鼬读取未定义的属性“查找”

Question

我看到了一些像我这样的问题，但找不到任何有效的解决方案，所以我想我会问。

我正在尝试从数据库中提取所有数据，以便我可以在应用程序中选择其中的部分数据。我的数据库工作正常，但是当我尝试提取图片时，它失败了，并一直给我这个错误，而且似乎也没有从数据库接收数据：

TypeError: Cannot read property 'find' of undefined

我安装了猫鼬，所有东西都连接起来，所以我不明白为什么它不能识别 find 属性。如果有人有任何想法，我的代码如下。

// Dependencies
var express = require("express");
var bodyParser = require("body-parser");
var mongoose = require("mongoose");
var exphbs = require("express-handlebars");
var request = require("request");

// var weapons = require("./weapons.js");

// Set mongoose to leverage built in JavaScript ES6 Promises
mongoose.Promise = Promise;


// Initialize Express
var app = express();

// Use morgan and body parser with our app
app.use(bodyParser.urlencoded({
  extended: false
}));

// Make public a static dir
app.use(express.static(__dirname + "/public"));

app.engine("handlebars", exphbs({ defaultLayout: "main" }));
app.set("view engine", "handlebars");

// Database configuration with mongoose
mongoose.connect("mongodb://localhost/weaponsdb");
var db = mongoose.connection;

// Show any mongoose errors
db.on("error", function(error) {
  console.log("Mongoose Error: ", error);
});

// Once logged in to the db through mongoose, log a success message
db.once("open", function() {
  console.log("Mongoose connection successful.");
});

//routes to home page

app.get('/', function(req, res, next){

    res.render("index",{ title: 'Express' });

});

app.get('/app', function(req, res, next){

    res.render("app",{ layout: 'applayout' });

});

app.get("/all", function(req, res) {

  // Query: In our database, go to the weapon collection, then "find" everything
  db.weapon.find({}, function(error, found) {

    // Log any errors if the server encounters one
    if (error) {
      console.log(error);
    }
    // Otherwise, send the result of this query to the browser
    else {
      res.json(found);
    }
  });
});

$.getJSON("/all", function(data) {
    console.log(data)
  // For each entry of that json...
  for (var i = 0; i < data.length; i++) {
    // Append each of the weapons' properties to the table
    $("#results").append("<img src = " + data[i].Picture + " />");
  }
});

Answer 1

如果您正在使用，mongoose您应该schema为您的集合定义一个，然后您可以引用该架构：

var weaponSchema = mongoose.Schema({
     .... your model definition here ....
});

var Weapon = mongoose.model('weapon', weaponSchema);

比你能做的：

Weapon.find({})........