nice article
copy (in case the original goes offline).

Examples of two npm modules I've successfully published and used using the above guides:

• js-object-properties
• faker-datastore

gotchas

• If you follow the structure of my modules mentioned above be sure to change the main attribute in package.json from:
  
  "index.js"
  
  … to:
  
  "lib/index.js"

  Failure to do so will result in "cannot find package" messages when the module is required.

• to be able to perform the test regarding the local-global installation you'd have to first setup Node to search that location as well (see this note).
• Before you publish to npm you should test your package by means of publishing locally and then requiring it from another directory (from the REPL). This is explained in the guide linked above and the local global installation command is correctly given as:

  npm install . -g
            

  To verify the local-global installation do a:

  npm list -g --depth 0
              

  Alternatively (and to also allow some REPL-type testing), cd to some other directory, open a repl (node or nodejs) and require your package to test its newly added functionality.

  … however, after the initial local-global installation you will invariably encounter bugs that you will have to fix (locally again). After each fix you should do (from the root of your project):

  npm run build && npm install . -g
              

  During these (local) iterations (that don't get published to the public npm repository) you don't need to update the version in package.json.

  NB:To ensure that the package you installed locally-globally is visible to a Node REPL ensure that the main property in package.json is properly set to the location of the compiled (if you are using Babel) sources. E.g. I had in my package.json "main": "mul.js" which didn't work until I changed it to: "main": "lib/mul.js". This was necessary as my compiled code resided under lib/ as per the build line (again in package.json): "build" : "babel src --out-dir lib --source-maps"

  NB2: For the locally-globally test to succeed you need to ensure that your $NODE_PATH environment variable points to the location of the local-globally installed modules. E.g. in one case I had to add the following to my .bashrc:

                export NODE_PATH=$NODE_PATH:~/.node_modules_global/lib/node_modules
              

  NB3: I have encountered cases where, even though the module was locally installed in the global location, it was still not visible to Webpack and I had to do an additional npm link. See this SO question of mine.

  At the end of a number of such iterations you are now able to publish to npm. Before you do that however, remember to update the version in package.json respecting semver.
  Once this is done do:

  npm publish
              

  However, even if you do forget to update package.json npm will baulk with an informative message, so no worries there.

  Afterwards, you are able to install your package from everywhere by name (rather than, e.g. having to point at a Github URL):

  npm install <your-package-name>
              

  You may also have to do a:

  npm update -g <your-package-name>
            

  … to ensure that your package has been updated in the global (local) repository (though if you've already installed it locally with npm install . -g you may not see any difference. At any rate you can use the following command to find the locally available version of your package:

  npm ls -g | grep <your-package-name>
            

• The interplay between the two ignore files:

  • .gitignore
  • .npmignore
… is terribly important as it can break your module and prevent clients from successfully requiring it.

Both files need to be present as different sets of files should be ignored by git and npm. For instance:

• The src/ directory should be ignored by npm but included by git
• The lib/ directory should be ignored by git but included by npm

A typical erroneous case I encountered during local global testing was that the lib/ directory in the local global publishing location included only the index.js file but not an app.js it required. I assume the lib/index.js file was included because it is explicitly identified in package.json:

$ cat package.json | grep main
  "main": "lib/index.js",
          

As a result, I had this situation:

$ ls /home/mperdikeas/.node_modules_global/lib/node_modules/filtered-datastore/lib/
total 12
drwxrwxr-x 2 mperdikeas mperdikeas 4096 Jun 13 12:08 ./
drwxrwxr-x 6 mperdikeas mperdikeas 4096 Jun 13 12:08 ../
-rw-rw-r-- 1 mperdikeas mperdikeas  113 Jun 13 12:08 index.js
          

… whereas when I properly added a .npmignore file I got (after the next npm install . -g) the following situation:

$ ls /home/mperdikeas/.node_modules_global/lib/node_modules/filtered-datastore/lib/
total 24
drwxrwxr-x 2 mperdikeas mperdikeas 4096 Jun 13 12:16 ./
drwxrwxr-x 5 mperdikeas mperdikeas 4096 Jun 13 12:16 ../
-rw-rw-r-- 1 mperdikeas mperdikeas 3739 Jun 13 12:15 app.js
-rw-rw-r-- 1 mperdikeas mperdikeas 3551 Jun 13 12:15 app.js.map
-rw-rw-r-- 1 mperdikeas mperdikeas  113 Jun 13 12:15 index.js
-rw-rw-r-- 1 mperdikeas mperdikeas  229 Jun 13 12:15 index.js.map
        

Refer to my filtered datastore module for correct .npmignore and .gitignore files.