本地正常的Node.js应用部署到Render.com时出现模块找不到错误

问题情况 #

本地运行正常的Node.js代码，部署到Render平台后无法启动，报错找不到./User模块。涉及的两个文件userModel.js和User.js位于同一目录。

错误日志 #

Mar 14 09:11:24 PM  ==> Starting service with 'npm start'

Mar 14 09:11:27 PM

Mar 14 09:11:27 PM  > login_schedule@1.0.0 start /opt/render/project/src

Mar 14 09:11:27 PM  > cross-env ISDEV=true node ./src/app.js

Mar 14 09:11:27 PM

Mar 14 09:11:33 PM  internal/modules/cjs/loader.js:888

Mar 14 09:11:33 PM    throw err;

Mar 14 09:11:33 PM    ^

Mar 14 09:11:33 PM

Mar 14 09:11:33 PM  Error: Cannot find module './User'

Mar 14 09:11:33 PM  Require stack:

Mar 14 09:11:33 PM  - /opt/render/project/src/src/model/userModel.Js

Mar 14 09:11:33 PM  - /opt/render/project/src/src/controller/registerUserController.js

Mar 14 09:11:33 PM  - /opt/render/project/src/src/router.js

Mar 14 09:11:33 PM  - /opt/render/project/src/src/app.js

Mar 14 09:11:33 PM      at Function.Module._resolveFilename (internal/modules/cjs/loader.js:885:15)

Mar 14 09:11:33 PM      at Function.Module._load (internal/modules/cjs/loader.js:730:27)

Mar 14 09:11:33 PM      at Module.require (internal/modules/cjs/loader.js:957:19)

Mar 14 09:11:33 PM      at require (internal/modules/cjs/helpers.js:88:18)

Mar 14 09:11:33 PM      at Object.<anonymous> (/opt/render/project/src/src/model/userModel.Js:1:14)

Mar 14 09:11:33 PM      at Module._compile (internal/modules/cjs/loader.js:1068:30)

Mar 14 09:11:33 PM      at Object.Module._extensions..js (internal/modules/cjs/loader.js:1097:10)

Mar 14 09:11:33 PM      at Module.load (internal/modules/cjs/loader.js:933:32)

Mar 14 09:11:33 PM      at Function.Module._load (internal/modules/cjs/loader.js:774:14)

Mar 14 09:11:33 PM      at Module.require (internal/modules/cjs/loader.js:957:19) {

Mar 14 09:11:33 PM    code: 'MODULE_NOT_FOUND',

Mar 14 09:11:33 PM    requireStack: [

Mar 14 09:11:33 PM      '/opt/render/project/src/src/model/userModel.Js',

Mar 14 09:11:33 PM      '/opt/render/project/src/src/controller/registerUserController.js',

Mar 14 09:11:33 PM      '/opt/render/project/src/src/router.js',

Mar 14 09:11:33 PM      '/opt/render/project/src/src/app.js'

Mar 14 09:11:33 PM    ]

Mar 14 09:11:33 PM  }

Mar 14 09:11:33 PM  npm ERR! code ELIFECYCLE

Mar 14 09:11:33 PM  npm ERR! errno 1

Mar 14 09:11:33 PM  npm ERR! login_schedule@1.0.0 start: `cross-env ISDEV=true node ./src/app.js`

Mar 14 09:11:33 PM  npm ERR! Exit status 1

Mar 14 09:11:33 PM  npm ERR!

Mar 14 09:11:33 PM  npm ERR! Failed at the login_schedule@1.0.0 start script.

Mar 14 09:11:33 PM  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

Mar 14 09:11:33 PM

Mar 14 09:11:33 PM  npm ERR! A complete log of this run can be found in:

Mar 14 09:11:33 PM  npm ERR!     /opt/render/.cache/_logs/2023-03-15T00_11_33_673Z-debug.log

问题原因 #

Render平台使用Linux系统，文件名严格区分大小写；而你的本地环境（如Windows或默认配置的macOS）对文件名大小写不敏感。这导致本地能正常匹配的文件引用，到Linux环境下因大小写不一致找不到模块。

从日志可看出，代码里引用的是./User，但实际部署后的文件存在大小写不匹配情况（比如文件实际是user.js而非User.js，或引用写成./user但文件是User.js）。

解决方案 #

• 统一文件名与引用的大小写：确保所有文件的命名和代码中的require引用完全一致，包括字母大小写。
  • 若模型文件名叫User.js，则userModel.js里的引用必须是：

    const User = require('./User')
    

  • 若文件名是user.js，则引用要改成：

    const User = require('./user')
    

• 排查所有文件的大小写：检查项目中所有文件的命名，避免出现大小写不一致的情况，尤其是跨系统部署时。

代码修正示例 #

假设模型文件实际是User.js，确保userModel.js的引用正确：

// userModel.js 正确引用
const User = require('./User')

// 其余代码保持不变
const getUserByEmail = async(email) =>{
    try{
        const user = await User.findOne({email})
        return user
    }catch(err){        
        throw new Error("Ocorreu um erro no servidor")
    }
}
// ... 其他函数

内容的提问来源于stack exchange，提问作者Pdtroia