Bye npm, Hello Git repository.

npm2git.js

'use strict'
/*
 * Rewrite package.json to get dependencies from Git repository instead of npm.
 *
 * See also: https://medium.com/@azerbike/i-ve-just-liberated-my-modules-9045c06be67c
 * and: http://blog.npmjs.org/post/141577284765/kik-left-pad-and-npm
 *
 * Usage: cd /path/to/your/package && node npm2git
 *
 * This script is warning because:
 *
 *   - this is forgotten dependencies' version information.
 *   - Git repository dose not contain all package files always.
 *
 * You will be happened some troubles in many case.
 *
 * Author: TSUYUSATO Kitsune (GitHub: @MakeNowJust, Twitter: @make_now_just)
 * License: WTFPL <http://www.wtfpl.net/txt/copying/>
 *
 * If you have some idea to improve, you could fork this Gist, thanks;)
 */

const fs = require('fs')

const pkg = require('./package.json')

const npm2git = field => {
  if (!pkg[field]) return

  for (let name of Object.keys(pkg[field])) {
    pkg[field][name] = require(`./node_modules/${name}/package.json`).repository.url || (()=> {
      console.error(`${name} has no repository field`)
      return pkg[field][name]
    })()
  }
}

'dependencies devDependencies peerDependencies optionalDependencies'
  .split(' ')
  .forEach(npm2git)

const json = JSON.stringify(pkg, null, '  ')
console.log(json)
fs.writeFileSync('package.json', json)

Thanks. I'm thinking along the same lines.