#Purpose

The module linker is a tool to recursively link and resolve local dependencies such that local modules can be required by name instead of their relative path.

#Behavior

It uses 'npm link' the linking and 'act-on-modules' project to find modules (recursively traversing directories and stopping whenever it finds a package.json file).

#Usage

##linker

###Description

This method will recursively traverse a series of directories it is given and globally link (to make available to the resolver) any module it finds.

Additionally, you can specify the tool (as a string) that will perform the link as a string (only 'npm' and 'yarn' are supported). If omitted, npm is assumed.

###Signature

const moduleLinker = require('module-linker');
moduleLinker.linker([<Strings of paths containing modules that will be required>], <tool>) //Returns a promise

###Example

//Linking with the default choice of npm
const moduleLinker = require('module-linker');
moduleLinker.linker(['/home/eric/nodeJsModules']).then(() => {
    console.log('all done');
});

//Linking with yarn
const moduleLinker = require('module-linker');
moduleLinker.linker(['/home/eric/nodeJsModules'], 'yarn').then(() => {
    console.log('all done');
});

##resolver

###Description

This method will recursively traverse a series of directories it is given and resolve any local dependencies it finds. Dependencies need to be indicated in the localDependencies entry of package.json files.

Additionally, you can specify the tool (as a string) that will perform the resolution as a string (only 'npm' and 'yarn' are supported). If omitted, npm is assumed.

###Signature

const moduleLinker = require('module-linker');
moduleLinker.resolver([<Strings of paths containing code that has local dependencies that need to be resolved>], <tool>) //Returns a promise

###Example

//Resolving with the default choice of npm
const moduleLinker = require('module-linker');
moduleLinker.resolver(['/home/eric/app', '/home/eric/nodeJsModules']).then(() => {
    console.log('all done');
});

//Resolving with yarn
const moduleLinker = require('module-linker');
moduleLinker.resolver(['/home/eric/app', '/home/eric/nodeJsModules'], 'yarn').then(() => {
    console.log('all done');
});

##call

###Description

A direct call to the library will call both the linker and resolver (sequentially as the resolver is dependent on the linker being finished).

Additionally, you can specify the tool (as a string) that will perform the resolution as a string (only 'npm' and 'yarn' are supported). If omitted, npm is assumed.

###Signature

const moduleLinker = require('module-linker');
moduleLinker([<Strings of paths containing code that has local dependencies that need to be resolved>], [<Strings of paths containing modules that will be required>], <tool>) //Returns a promise

###Example

//Using default choice of npm
const moduleLinker = require('module-linker');
moduleLinker(['/home/eric/app', '/home/eric/nodeJsModules'], ['/home/eric/nodeJsModules']).then(() => {
    console.log('all done');
});

//Using yarn
const moduleLinker = require('module-linker');
moduleLinker(['/home/eric/app', '/home/eric/nodeJsModules'], ['/home/eric/nodeJsModules'], 'yarn').then(() => {
    console.log('all done');
});

##Package.json pre-requisites

There are two pre-requisites in package.json files for the library to work as intended.

• All modules that are to be required, need to have a legal unique (within the project) module name. This is the 'name' entry in the package.json file
• All modules that have local dependencies, need to have a "localDependencies" in their package.json file listing their local dependencies as an array of strings. This is a custom entry that is used solely by the library.

Ex:

{
  "name": "sample-app",
  "version": "1.0.0",
  "main": "index.js",
  "licenses": [
    {
      "type": "MIT License",
      "url": "http://mit-license.org/"
    }
  ],
  "dependencies": {
  },
  "devDependencies": {
  },
  "localDependencies": ["user-store"],
  "license": "MIT",
  "directories": {
  },
  "scripts": {
      "start": "node index.js"
  }
}

##Running Tests

Run npm test run npm to test this module with npm

Run npm test run yarn to test this module with yarn

Because I didn't want the tests to pollute anyone's global space with throwaway test modules, I dockerized them so you'll need docker and docker-composed installed (as well as a user with enough privilege to execute docker without sudo) to run the tests.

##Installation

Run npm install module-linker