Javascript 抛出新错误（'；猫鼬未连接'；）； 因此，我尝试在express中使用mongoose gridfs模块，但在尝试运行express服务器时出现以下错误。

我的连接字符串是否正常，但我似乎无法理解。我真的需要帮助。谢谢大家

正如您从跟踪中看到的，当它尝试创建

GridFSStorage

实例并抛出错误时，会发生问题，因为mongoose尚未就绪：

错误：Mongoose未连接
在新建GridFSStorage（C:\Users\BARMAN\Documents\Codes\zubis mart\node） _modules\mongoose gridfs\lib\storage.js:43:11）

在连接gridfs之前，确保mongoose已连接到db

下面是修复程序：

const express = require('express');
const bcrypt = require('bcryptjs');
const fs = require('fs');
const mongoose = require('mongoose');
const mongooseGridFS = require('mongoose-gridfs');
const multer = require('multer');
const passport = require('passport');


const config = require('../config/database');

mongoose.connect(config.database, {
    useNewUrlParser: true
});

let conn = mongoose.connection;

conn.once('open', () => {
    console.log('Database File Upload Connection Established Successfully.');

    global.gridfs = mongooseGridFS({
      collection: 'images',
      model: 'Image',
      mongooseConnection: conn
    });
});

conn.on('error', (err) => {
    console.log('File Connection Error... ' + err);
});

顺便说一句，我读到的精神错乱与你的问题完全一样，这是不正确的。

---

因为在源代码中，它会立即检查连接状态，这表明文档不正确。

您应该确保先打开连接，然后初始化gridfs

conn.once('open', () => {
    global.gridfs = mongooseGridFS({
      collection: 'images',
      model: 'Image',
      mongooseConnection: conn
    });
});

---

谢谢，这很有效。但是现在我无法从另一个块访问gridfs变量。那么如何访问用“global”关键字定义的变量呢？

const express = require('express');
const bcrypt = require('bcryptjs');
const fs = require('fs');
const mongoose = require('mongoose');
const mongooseGridFS = require('mongoose-gridfs');
const multer = require('multer');
const passport = require('passport');


const config = require('../config/database');

mongoose.connect(config.database, {
    useNewUrlParser: true
});

let conn = mongoose.connection;

conn.once('open', () => {
    console.log('Database File Upload Connection Established Successfully.');

    global.gridfs = mongooseGridFS({
      collection: 'images',
      model: 'Image',
      mongooseConnection: conn
    });
});

conn.on('error', (err) => {
    console.log('File Connection Error... ' + err);
});

conn.once('open', () => {
    global.gridfs = mongooseGridFS({
      collection: 'images',
      model: 'Image',
      mongooseConnection: conn
    });
});