Introduction

As part of the process of working in node.js applications, developers usually use additional libraries and frameworks to ease and speed their development time, and more than often the number of libraries they rely upon is quite high.

It is also not uncommon to need to modify any of those libraries to fix a bug, or fork them to add additional functionality required for the project they are being used in.

The usual way to do this in a node.js project is:

  1. Clone the library's repository in your local machine
  2. cd your library's folder.
  3. sudo npm link to link the module globally.
  4. cd to your project's folder.
  5. npm link <library_name> to link to the library.

If you have multiple libraries that you need to be linking at the same time, or you have to link a library that depends on another library that you may need to link as well, it can be quite cumbersome to link them one by one.

In my free time I developed mdlink. It is a small utility that allows to easily npm link multiple node modules in a given project.

It was born as a reaction of my annoyance while I was developing Ember.js applications with multiple addons at the same time. Per each addon I'd need to clone it and link it. This tool intends to provide an easy way of bulk npm link and removing those links later while not necessary.

Modules are specified in the mdlink.config.json configuration file. e.g:

{
  "base_modules_path": "~/gits/test",
  "modules": {
    "mdlink": {
      "url": "https://github.com/fr0gs/mdlink",
      "path": "~/gits/test/mdlink"
    }
  }
}

Each module to be linked is stated in the modules object. It can have both url & path together, or only one of each.

The base_modules_path is used for the case where there is no path but a url is yet specified. The module will be cloned in base_modules_path/module_name instead.

Let's see an example with a new Ember application. First, download mdlink with npm and create the application:

test-ember:master* λ sudo npm install -g mdlink
test-ember:master* λ ember new test-ember

Then, create a new mdlink.config.json file inside the test-ember app.

test-ember:master* λ mdlink init

And let's say that in our new application we want to locally modify both ember-moment and ember-promise-helpers. We modify the mdlink.config.json file like this:

{
  "base_modules_path": "/home/esteban/gits/test",
  "modules": {
    "ember-moment": {
      "url": "https://github.com/stefanpenner/ember-moment",
      "path": "/home/esteban/gits/test/ember-moment"
    },
    "ember-promise-helpers": {
      "url": "https://github.com/fivetanley/ember-promise-helpers.git",
      "path": "/home/esteban/gits/test/ember-promise-helpers"
    }
  }
}

Do the linking:

test-ember:master* λ mdlink s
[+] Path /home/esteban/gits/test-ember/node_modules/ember-moment already exists, removing it.
[+] <path exists> . Successfully cloned https://github.com/stefanpenner/ember-moment in path: /home/esteban/gits/test/ember-moment
[+] Create link from /usr/lib/node_modules/ember-moment -> /home/esteban/gits/test/ember-moment
-------------------------
[+] <path exists> . Successfully cloned https://github.com/fivetanley/ember-promise-helpers.git in path: /home/esteban/gits/test/ember-promise-helpers
[+] Create link from /usr/lib/node_modules/ember-promise-helpers -> /home/esteban/gits/test/ember-promise-helpers

Verify both modules where properly cloned:

test λ ls -la ~/gits/test/
drwxrwxr-x  4 esteban esteban 4,0K Dez 19 22:07 ./
drwxrwxr-x  8 esteban esteban 4,0K Dez 19 22:05 ../
drwxrwxr-x 10 esteban esteban 4,0K Dez 19 22:36 ember-moment/
drwxrwxr-x  9 esteban esteban 4,0K Dez 19 22:07 ember-promise-helpers/

Modify index.js in both modules, and ember s from the test-ember app folder:

test-ember:master* λ ember s
Linked ember-moment
Linked ember-promise-helpers
Could not start watchman
Visit https://ember-cli.com/user-guide/#watchman for more info.
Livereload server on http://localhost:7020

Build successful (14117ms) – Serving on http://localhost:4200/

Have fun!