Roosevelt

First declare fallback-dependencies as a dependency of your app.

Declare fallback-dependencies

Next, add a fallbackDependencies entry to your package.json alongside your dependencies, devDependencies, etc, e.g.:

"fallbackDependencies": {
  "dir": "lib",
  "repos": {
    "some-private-dependency": [
      "https://some.private.git.repo.somewhere",
      "https://some.private.git.repo.somewhere.else"
    ],
    "some-other-private-dependency": [
      "https://some.other.private.git.repo.somewhere",
      "https://some.other.private.git.repo.somewhere.else"
    ]
  }
}

API

• dir [String]: What directory to deposit fallback-dependencies into. Default: fallback_dependencies.
• repos [Object of Arrays of Strings]: A list of dependencies similar to the dependencies field in package.json, but instead of supplying a string for where to fetch it, you supply an array of strings of possible locations to fetch it from. This script will attempt to fetch it from the first location, then if that fails will fallback to the second possible place to get it from, and so on until it runs out of places to try. Default: {}.
• reposFile [String]: Relative path to a JSON file that contains a list of repos formatted the same as the repos entry. If both repos and reposFile are supplied, the two lists will be merged. Default: {}.

Example of reposFile usage:

// fallback-dependencies.json
{
  "some-private-dependency": [
    "https://some.private.git.repo.somewhere",
    "https://some.private.git.repo.somewhere.else"
  ],
  "some-other-private-dependency": [
    "https://some.other.private.git.repo.somewhere",
    "https://some.other.private.git.repo.somewhere.else"
  ]
}

All params are optional, but the module won't do anything unless you supply at least repos or reposFile.

Fetch fallback-dependencies with a postinstall script

Lastly, add a postinstall script to your npm scripts to execute the fallback-dependencies script after you install other dependencies:

"scripts": {
  "postinstall": "node node_modules/fallback-dependencies/fallback-dependencies.js"
},

You can also write your postinstall script to fail silently if the fallback-dependencies.js file is not found for whatever reason, e.g.:

"scripts": {
  "postinstall": "node -e \"try { require('child_process').spawnSync('node', ['node_modules/fallback-dependencies/fallback-dependencies.js'], { shell: false, stdio: 'ignore' }) } catch (e) {}\""
},

Writing the postinstall script that way might be a little ugly, but it's useful to do it this way if fallback-dependencies is a devDependency of your app and you don't want the postinstall script to fail when you do a production dependencies-only build.