如何解决“找不到模块"使用 Node.js 时出错? [英] How do I resolve "Cannot find module" error using Node.js?

问题描述

从 GitHub 中提取模块并按照说明进行构建后，我尝试使用以下方法将其提取到现有项目中:

After pulling down a module from GitHub and following the instructions to build it, I try pulling it into an existing project using:

> npm install ../faye

这似乎可以解决问题:

> npm list
/home/dave/src/server
└─┬ faye@0.7.1
  ├── cookiejar@1.3.0
  ├── hiredis@0.1.13
  └── redis@0.7.1

但是 Node.js 找不到模块:

But Node.js can't find the module:

> node app.js
node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
Error: Cannot find module 'faye'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at require (module.js:368:17)
    at Object.<anonymous> (/home/dave/src/server/app.js:2:12)
    at Module._compile (module.js:432:26)
    at Object..js (module.js:450:10)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)
    at Array.0 (module.js:470:10)

我真的很想了解这里发生了什么，但我不知道下一步该往哪里看.有什么建议吗?

I really want to understand what is going on here, but I'm at a bit of a loss as to where to look next. Any suggestions?

推荐答案

使用 npm install 仅将模块安装到当前目录(在名为 node_modules 的子目录中).app.js 是否位于 home/dave/src/server/ 下?如果没有，并且您想从任何目录使用该模块，则需要使用 npm install -g 全局安装它.

Using npm install installs the module into the current directory only (in a subdirectory called node_modules). Is app.js located under home/dave/src/server/? If not and you want to use the module from any directory, you need to install it globally using npm install -g.

我通常在本地安装大多数软件包，以便将它们与我的项目代码一起签入.

I usually install most packages locally so that they get checked in along with my project code.

更新 (8/2019):

现在你可以使用 package-lock.json 文件，它会自动当 npm 修改您的 node_modules 目录时生成.因此，您可以不签入包，因为 package-lock.json 会跟踪您当前正在使用的 node_modules 的确切版本.要从 package-lock.json 而不是 package.json 安装包，请使用命令 npm ci.

Nowadays you can use package-lock.json file, which is automatically generated when npm modifies your node_modules directory. Therefore you can leave out checking in packages, because the package-lock.json tracks the exact versions of your node_modules, you're currently using. To install packages from package-lock.json instead of package.json use the command npm ci.

更新 (3/2016):

我的回复收到了很多批评，特别是我检查了我的代码所依赖的包.几天前，有人取消发布他们所有的包(https://kodfabrik.com/journal/i-ve-just-liberated-my-modules) 破坏了 React、Babel 和几乎所有其他内容.希望现在很清楚，如果你有生产代码，你不能依赖 NPM 实际上为你维护你的依赖项.

I've received a lot of flak for my response, specifically that I check in the packages that my code depends on. A few days ago, somebody unpublished all of their packages (https://kodfabrik.com/journal/i-ve-just-liberated-my-modules) which broke React, Babel, and just about everything else. Hopefully it's clear now that if you have production code, you can't rely on NPM actually maintaining your dependencies for you.

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