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

问题描述

从GitHub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拖入现有项目中:

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的事情，但是我对接下来的去向有些困惑.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中(在名为node_modules的子目录中). app.js是否位于home/dave/src/server/下?如果不是，并且您想从任何目录使用该模块，则需要使用npm install -g在全局范围内进行安装.

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，以便它们与我的项目代码一起被检入.

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

更新(8/2019):

Update (8/2019):

如今，您可以使用 package-lock.json 文件，该文件会自动npm修改您的node_modules目录时生成.因此，您可以省去签入包，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安装软件包，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):

Update (3/2016):

我收到了很多回应，特别是我检入了我的代码所依赖的软件包.几天前，有人取消发布了所有软件包( https://kodfabrik .com/journal/i-ve-just-liberated-my-modules )破坏了React，Babel和其他所有功能.希望现在很清楚，如果您具有生产代码，则不能依赖NPM实际为您维护依赖项.

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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