module.filename 未定义（续集，Node.js）

Question

我正在阅读 this Sequelize 教程和 Node.js。我在第 4 行收到以下错误：

TypeError：路径必须是字符串。收到未定义

const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
const basename = path.basename(module.filename);
const env = process.env.NODE_ENV || 'development';
const config = require(`${__dirname}/../config/config.json`)[env];
const db = {};

let sequelize;
if (config.use_env_variable) {
  sequelize = new Sequelize(process.env[config.use_env_variable]);
} else {
  sequelize = new Sequelize(
    config.database, config.username, config.password, config
  );
}
fs
  .readdirSync(__dirname)
  .filter(file =>
    (file.indexOf('.') !== 0) &&
    (file !== basename) &&
    (file.slice(-3) === '.js'))
  .forEach(file => {
    const model = sequelize.import(path.join(__dirname, file));
    db[model.name] = model;
  });

Object.keys(db).forEach(modelName => {
  if (db[modelName].associate) {
    db[modelName].associate(db);
  }
});

db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;

似乎 module.filename 未定义。我不知道为什么会这样（我是 Node 的新手）并且与教程和我的应用程序的唯一区别是我不使用 express api （但是 GraphQL）并且我的 sequelize 自动生成的文件夹位于在 ../postgres/ 而不是 ../

编辑：

如果我运行教程回购并打印 module.filename 我得到 /Users/Creece/Downloads/postgres-express-node-tutorial-master/server/models/index.js

现在，如果我手动分配 module.filename，如下所示：module.filename = '/Users/Creece/Downloads/express_graphql_hmr_article_boilterplate-master/server/postgres/models/index.js';（在分配基本名称常量之前），我会在 const model = ... 上收到一个新的奇怪错误行：

Error: Cannot find module '/Users/Creece/Downloads/express_graphql_hmr_article_boilerplate-master/server/dist/postgres/models/todo.js'

请注意，上述路径中的文件夹 "dist" 是 webpack 的（虽然不确定，但它不是我的）。

编辑 2：（关于我对@NikMartin 的回答的评论

这是 Sequelize 自动生成的文件。/postgres/models/todo.js:

module.exports = (sequelize, DataTypes) => {

  const Todo = sequelize.define('Todo', {
    title: {
      type: DataTypes.STRING,
      allowNull: false,
    },
  });



  Todo.associate = (models) => {
    Todo.hasMany(models.TodoItem, {
      foreignKey: 'todoId',
      as: 'todoItems',
    });
  };
  return Todo;

};

解决方案（基于接受的答案）：

const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
//const basename = path.basename(__filename);
const env = process.env.NODE_ENV || 'development';
const config = require(`${__dirname}/../config/config.json`)[env];
const db = {};

let sequelize;
if (config.use_env_variable) {
  sequelize = new Sequelize(process.env[config.use_env_variable]);
} else {
  sequelize = new Sequelize(
    config.database, config.username, config.password, config
  );
}

const models = [
  require('./Todo')(sequelize, Sequelize),
  require('./TodoItem')(sequelize, Sequelize),
];

models.forEach(model => {
  db[model.name] = model;
});

models.forEach(model => {

  if (db[model.name].associate) {
    console.log("entered");
    db[model.name].associate(db);
  }
});

db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;

Answer 1

关于 module.filename 问题 - 您可以阅读此讨论或仅阅读评论：https://github.com/webpack/webpack/issues/1599#issuecomment-328540024

引用：

aprilmintacpineda commented

for those having this issue, it is also good to note that module.filename would be undefined if you bundled your files. In my case it was undefined and I fixed it by simply replacing it with __filename which yields the same outcome.

因此您应该可以将 path.basename(module.filename); 替换为 path.basename(__filename);。

但据我所知，它仍然是 /dist 文件夹中的捆绑 js 文件，而您的模型位于 /postgres/models 文件夹中。

我看到这里有两个选项：

1) 不自动加载模型，而是直接请求所有必要的模型。

假设这个文件的路径是/postgres/models/index.js并且实际模型在同一个文件夹 未测试

const Sequelize = require('sequelize');
const env = process.env.NODE_ENV || 'development';
const config = require(`${__dirname}/../config/config.json`)[env];
const db = {};

let sequelize;
if (config.use_env_variable) {
  sequelize = new Sequelize(process.env[config.use_env_variable]);
} else {
  sequelize = new Sequelize(
    config.database, config.username, config.password, config
  );
}

// removed autoloading block

// setting the list of used models
const models = [
  require('./TodoItem')(sequelize, Sequelize),
  require('./Comment')(sequelize, Sequelize)
];

// registering models by their names
models.forEach(model => {
  db[model.name] = model;
});

// using registered models to set up relations
models.forEach(model => {
  if (model.associate) {
    model.associate(db);
  }
});

db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;

这意味着灵活性降低，但您的捆绑代码将开始使用捆绑模型。我想对于 dist 代码来说，需要一些 "external"（缺少内部模型）非配置 js 文件才能工作并不是最好的事情。

2) 不是从当前文件夹而是从定义的文件夹加载文件。

将 /postgres/models/index.js 从模型文件夹移出到 /postgres/index.js（这样模型文件夹将只有实际的模型文件）
从文件中删除 basename
而不是 .readdirSync(__dirname) 使用 .readdirSync(__dirname + "/../postgres/models")
删除 (file !== basename) && 检查（因为没有必要）

无论哪种方式，替换模块的属性 (module.filename) 都不是解决方案。

Answer 2

这可以简化为：

const config = require('../config/config')['development']
const {Sequelize} = require('sequelize');
const sequelize = new Sequelize(config['dbUrl']);
const db = {};
const models = [];

sequelize.authenticate()
    .then(() => console.log('Connection has been established successfully.'))
    .catch(err => console.error('Unable to connect to the database:', err));

const modules = [
    require('./user'),
    require('./post'),
    require('./comment')
]

modules.forEach(module => {
    const model = module(sequelize, Sequelize)
    db[model.name] = model
    models.push(model)
});

models.forEach(model => {
    if (db[model.name].associate) {
        db[model.name].associate(db)
    }
});

module.exports = {...db, sequelize, Sequelize};

module.filename 未定义（续集，Node.js）

module.filename is undefined (Sequelize, Node.js)

javascript

postgresql

node.js

postgresql-9.6

我看到这里有两个选项：