运行 npm 全局安装包

Question

Can someone please explain how do node's globally installed behave. It is really confusing me. If I install a package (with executables) such as http-server globally I can run it with:

http-server

But if I do

node http-server

I get

module.js:339
    throw err;
    ^

Error: Cannot find module '/path/to/current/dir/http-server'
    at Function.Module._resolveFilename (module.js:337:15)
    at Function.Module._load (module.js:287:25)
    at Function.Module.runMain (module.js:457:10)
    at startup (node.js:136:18)
    at node.js:972:3

I suspect my tern package in emacs is trying to run it with node hence breaking. Why is this happening? Why can't node find the path to it's own modules?

Answer 1

There are two ways installing packages: globally and locally .
Locally installed package files end up in your local node_modules (in your project folder where you called npm install some-package ).
Globally installed package files end up in your system so they are available in command line, if globally installed packages provides executable then you can invoke it in command line directly some-package (without node ), if it does not provide executable then you can use it in repl mode ( node ) like var package = require('some-package') and it is also available locally (inside your project folder even if you don't have it installed locally).

Answer 2

This started as a comment but got now a little longer.

The problem is not exactly node not finding global packages, node only searches for packages in the current location (like under under node_modules ), and that is by design. Globally installed packages can be run from the command like because of the way npm installs them, and this is what makes global packages special in some way.

On Unix based systems, npm creates soft links to the main executables of globally installed packages, like http-server in a folder in the executable path. On my machine, this is /usr/local/bin/ . This is why those commands can be invoked from the command line without specifying a full path.

On Windows, npm creates an executable batch file named for instance http-server.cmd under %APPDATA% (typically something like C:\Users\YourUserName\AppData\Roaming ). The batch file contains instructions to run the target executable from the location where it's actually installed.

Answer 3

rahul@Rahul-Machine:~$ node blalal 
module.js:338
throw err;
^

Error: Cannot find module '/home/rahul/blalal'
at Function.Module._resolveFilename (module.js:336:15)
at Function.Module._load (module.js:286:25)
at Function.Module.runMain (module.js:475:10)
at startup (node.js:117:18)
at node.js:951:3

ooh same error

this is because i first command you are actually trying to access a global variable but in second you are some where in your file hierarchy and from there you are saying that you want to access that package so you are wrong if you want to execute that global package try

whereis http-server

then go to that directory and find the file package.json and then open it and find the "main" property and there you get a file name then type

  node index.js

your file will be executed

Answer 4

This answer will help you run the npm node module on the command line if you haven't installed it globally. Either run it globally as they way you are doing. Other option is to give full path of local package file. For example I want to run a package live-server which is installed as package locally in my current directory.

node ./node_modules/live-server/live-server --port=5000 

Here(on my Mac) the live-server.js file is inside the live-server directory, Its optional to add.js and execute the command as below. Also port is optional argument for live-server

node ./node_modules/live-server/live-server.js --port=5000 

Answer 5

When you install something globally you store a variable with a stored path linking to it as well as the execution program. While your operating system will know how to access it. Node will not. If you want to "node something.js" you much either be in the directory it is or adjust your path so that node knows how to get to the file. for instance node "c:/jsapps/main/app.js" or if you were in lets say the folder 'jsapps' you would type node "main/app.js" to execute the same file.