Javascript 使用 NPM 安装时找不到 Express 模块

Express module not found when installed with NPM

提问by Kelp

When I try to run the app.jsfile created by express, I get the following error:

当我尝试运行app.js由 express 创建的文件时，出现以下错误：

$ node app.js

node.js:134
        throw e; // process.nextTick error, or 'error' event on first tick
        ^
Error: Cannot find module 'express'
    at Function._resolveFilename (module.js:320:11)

When I type in express --versionI get a return statement of 2.3.3. I used npm to install express. I had to manually make npm using these instructions:

当我输入时，express --version我得到一个 return 语句2.3.3。我使用 npm 安装 express。我必须使用以下说明手动制作 npm：

git clone http://github.com/isaacs/npm.git
cd npm
sudo make install

The error is Error: Cannot find module 'express'.

错误是Error: Cannot find module 'express'。

Do I need to do something after installing npm and express in order to make express see the modules created by npm?

安装 npm 和 express 后我需要做些什么才能让 express 看到 npm 创建的模块吗？

• My node is version: 0.4.6
• My express is version: 2.3.3
• My npm is version: 1.0.6

• 我的节点是版本：0.4.6
• 我的快递是版本：2.3.3
• 我的 npm 是版本：1.0.6

Express is installed globally. I used the -gflag to install it.

Express 是全局安装的。我使用-g标志来安装它。

---

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Edit:When I try "node -e require.paths"I get:

编辑：当我尝试时，"node -e require.paths"我得到：

[ '/home/user/.node_modules',
  '/home/user/.node_libraries',
  '/usr/local/lib/node' ]

So, node isn't detecting the npm installation. How do I get node to detect the npm installation?

因此，节点未检测到 npm 安装。如何让节点检测 npm 安装？

采纳答案by Gorm Casper

I had the same problem. This worked for me though:

我有同样的问题。不过这对我有用：

Seems like npm (now?) installs node modules to /usr/local/lib/node_modules/and not /usr/local/lib/node/

似乎 npm（现在？）安装节点模块/usr/local/lib/node_modules/而不是/usr/local/lib/node/

What I did was simply to copy everything from node_modules to node: sudo cp -r /usr/local/lib/node_modules/* usr/local/lib/node/and now it seems to be working for me.

我所做的只是将所有内容从 node_modules 复制到 node:sudo cp -r /usr/local/lib/node_modules/* usr/local/lib/node/现在它似乎对我有用。

Hope this helps you :-)

希望这对你有帮助:-)

回答by just_a_dude

• Install express

  npm install -g express

• Create a new app

  express your_app

• cd into app directory

  cd your_app

• use npm link to resolve modules

  npm link express

• 安装快递

  npm install -g express

• 创建新应用

  express your_app

• cd 进入应用程序目录

  cd your_app

• 使用 npm 链接解析模块

  npm link express

回答by isaacs

Use local installs for require(), and global installs for command-line apps.

对 require() 使用本地安装，对命令行应用程序使用全局安装。

If you need both, use the npm linkcommand.

如果两者都需要，请使用该npm link命令。

回答by ezraspectre

On Ubuntu 12.04 you have to add the export NODE_PATH=/usr/local/lib/node_modulesto your /.bashrc to use globally installed modules.

在 Ubuntu 12.04 上，您必须将 添加export NODE_PATH=/usr/local/lib/node_modules到 /.bashrc 以使用全局安装的模块。

回答by Rob Raisch

It appears that while npm had been updated to install global modules into /usr/local/lib/node_modules, Node's own require.pathsdoes not yet reflect this change.

看来，虽然 npm 已更新以将全局模块安装到 中/usr/local/lib/node_modules，但 Node 自己的require.paths尚未反映此更改。

There are two reasonable solutions:

有两种合理的解决方案：

1. Add the following code to the top of your application:

   require.paths.push('/usr/local/lib/node_modules');
   

   • Pro: non-invasive, easy to add

   • Con: requires discipline, future versions of node willrestrict access to require.paths

2. As root, execute:

   ln -s /usr/local/lib/node_modules /usr/local/lib/node
   

   • Pro: reasonably non-invasive

   • Con: requires root, modifies linux fs, might not survive system updates

1. 将以下代码添加到应用程序的顶部：

   require.paths.push('/usr/local/lib/node_modules');
   

   • 优点：非侵入性，易于添加

   • 缺点：需要纪律，节点的未来版本将限制访问require.paths

2. 以 root 身份执行：

   ln -s /usr/local/lib/node_modules /usr/local/lib/node
   

   • 优点：合理的非侵入性

   • 缺点：需要 root，修改 linux fs，可能无法在系统更新中存活

回答by Pier Paolo Ramon

What about NODE_PATH=/usr/local/lib/node_modulesin .bashrcor .bash_profile? I think it's the real correct way.

怎么样NODE_PATH=/usr/local/lib/node_modules在的.bashrc或.bash_profile中？我认为这是真正正确的方法。

回答by Lo?c

It may happen, if you're using windows, that the environment variable NODE_PATHis not set, and thus when you execute node fileName.jsit won't find the libraries.

如果您使用的是 Windows，可能会发生环境变量NODE_PATH未设置的情况，因此当您执行node fileName.js它时将找不到库。

Check for the variable on your console, and if not present, create it. Give it the NODE_HOME\node_modulesvalue, where NODE_HOMEis your node install dir. This path is where npm install puts every module upon downloading.

检查控制台上的变量，如果不存在，则创建它。给它NODE_HOME\node_modules值，NODE_HOME你的节点安装目录在哪里。这个路径是 npm install 在下载时放置每个模块的地方。

回答by buzzcoder

Set NODE_PATH=NODE_HOME\node_modules.

设置NODE_PATH=NODE_HOME\node_modules。

I'm using windows 7 and it works fine.

我正在使用 Windows 7，它工作正常。

回答by vapour

require.pathsis removed, use the NODE_PATHenvironment variable instead.

require.paths已删除，请改用NODE_PATH环境变量。

回答by orbiteleven

It looks like the easiest way to do this is to run npm installfrom your app's folder. This tells npm to hook everything up.

看起来最简单的方法是npm install从应用程序的文件夹中运行。这告诉 npm 连接所有东西。

It's the last instruction after express <appname>:

这是之后的最后一条指令express <appname>：

...
dont forget to install dependencies:
$ cd <appname> && npm install