Question

我正在关注MDN Express教程，但是我遇到了使用node populatedb命令的问题。它应该用集合填充我的mLab数据库，但它不会，我认为这是由于上面提到的参考错误。如果有人可以帮我解决这个参考错误，我们将不胜感激。

这是我的populatedb.js负责人：

console.log('This script populates some test books, authors, genres and bookinstances to your database. Specified database as argument - e.g.: populatedb mongodb://your_username:your_password@your_dabase_url');

// Get arguments passed on command line
var userArgs = process.argv.slice(2);
if (!userArgs[0].startsWith('mongodb://nathankyle625:*******.@ds137729.mlab.com:37729/local_library_express')) {
console.log('ERROR: You need to specify a valid mongodb URL as the first argument');
return
}

var async = require('async')
var Book = require('./models/book')
var Author = require('./models/author')
var Genre = require('./models/genre')
var BookInstance = require('./models/bookinstance')


var mongoose = require('mongoose');
var mongoDB = userArgs[0];
mongoose.connect(mongoDB);
mongoose.Promise = global.Promise;
var db = mongoose.connection;
mongoose.connection.on('error', console.error.bind(console, 'MongoDB 
connection error:'));

这是我的bookinstance.js：

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var BookInstanceSchema = new Schema(
{
book: { type: Schema.ObjectId, ref: 'Book', required: true }, 
 //reference to the associated book
imprint: {type: String, required: true},
status: {type: String, required: true, enum: ['Available', 
'Maintenance', 'Loaned', 'Reserved'], default: 'Maintenance'},
due_back: {type: Date, default: Date.now},
}
);

// Virtual for bookinstance's URL
BookInstanceSchema
.virtual('url')
.get(function () {
return '/catalog/bookinstance/' + this._id;
});

//Export model
module.exports = mongoose.model('BookInstance', BookInstanceSchema);

这是我在运行命令时所得到的：

express-locallibrary-tutorial nathanbeier$ node populatedb mongodb://nathankyle625:*******.@ds137729.mlab.com:37729/local_library_express  

ReferenceError: BookInstanceSchema is not defined
at Object.<anonymous> (/Users/nathanbeier/Desktop/express-locallibrary-
tutorial/models/genre.js:10:1)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Object.<anonymous> (/Users/nathanbeier/Desktop/express-locallibrary-tutorial/populatedb.js:15:13)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Function.Module.runMain (module.js:684:10)
at startup (bootstrap_node.js:187:16)

Answer 1

您的代码看起来不错，但您错过了./models/genre.js文件而不是./models/bookinstance.js引发的错误，请尝试从文件BookInstanceSchema中删除genre.js行，或者将其重命名为genre.js.save，然后重试。

运行节点populatedb <mymongodburl>时出现RefError

1 个答案: