部署到 Heroku 时出现 Webpack 错误（npm 退出状态 2）

Question

我和我的队友正在尝试部署到 Heroku，但我们已经多次遇到这种令人困惑的错误/构建失败。

我们已经解决的问题包括：

1. 确保 devDependencies 在 Dependencies 中
2. 已删除并重新安装 Wepback
3. 已删除锁定文件
4. 清除了 npm 缓存
5. 创建了一个新的 heroku 应用程序并尝试从新开始在那里部署

这些都不起作用，我们非常感谢您的帮助。谢谢！

    remote: -----> Building dependencies
    remote:        Installing node modules (package.json + package-lock)
    remote:
    remote:        > sensation-mapping@0.0.1 postinstall /tmp/build_165cca2bcbc98089b28e7f67a5aa96ab
    remote:        > webpack
    remote:
    remote:        Hash: be40b95d0b5157875598
    remote:        Version: webpack 3.12.0
    remote:        Time: 1767ms
    remote:        Asset    Size  Chunks                    Chunk Names
    remote:        bundle.js  801 kB       0  [emitted]  [big]  main
    remote:        bundle.js.map  943 kB       0  [emitted]         main
    remote:        [12] ./client/index.js 543 bytes {0} [built]
    remote:        + 24 hidden modules
    remote:
    remote:        ERROR in ./client/index.js
    remote:        Module not found: Error: Can't resolve './components/App' in '/tmp/build_165cca2bcbc98089b28e7f67a5aa96ab/client'
    remote:        @ ./client/index.js 11:11-38
    remote:        npm ERR! code ELIFECYCLE
    remote:        npm ERR! errno 2
    remote:        npm ERR! sensation-mapping@0.0.1 postinstall: `webpack`
    remote:        npm ERR! Exit status 2
    remote:        npm ERR!
    remote:        npm ERR! Failed at the sensation-mapping@0.0.1 postinstall script.
    remote:        npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
    remote:
    remote:        npm ERR! A complete log of this run can be found in:
    remote:        npm ERR!     /tmp/npmcache.6UwNM/_logs/2018-06-07T02_48_08_002Z-debug.log
    remote:
    remote: -----> Build failed

Answer 1

您可以尝试解决问题的方法：

1. 检查日志是否有任何问题。
2. 检查代码中是否存在对可能被调用但不存在的模块的任何缺失引用。
3. 完成上述步骤后，再次尝试构建，看看会发生什么。