@yarnpkg/plugin-optional-resolution

Yarn Berry plugin that adds support for non-existing optional package dependencies. Without this plugin Yarn 2+ ("Berry") installing or adding an optional package which does not exist in the package repository will result in an error:

➤ YN0027: <pkg>@unknown can't be resolved to a satisfying range
➤ YN0035: The remote server failed to provide the requested resource
➤ YN0035:   Response Code: 404 (Not Found)
➤ YN0035:   Request Method: GET
➤ YN0035:   Request URL: https://registry.yarnpkg.com/<pkg>

This plugin changes this behavior in two ways:

1. If an optional package requested from any defined NPM package registry (see npmRegistryServer and npmScopes), would lead to a 404 (Not Found) error, this package instead, serves Yarn a "fake" / dummy package metadata file, leading to an optional-pkg instead, which satisfies the requested version range.

2. Before packing, this plugin will "realize" all those optional, but non-existent, packages, by removing them from the "optionalDependencies" section before publishing. This allows others to consume the package, without requiring the optional resolution plugin, or even with other package managers like NPM.

This makes "optionalDependencies" truly optional, in a sense that they do not even need to exist, which behaves according to the NPM package specification. Sometimes you favour a behavior like this, especially if you are working e.g. with multiple private package registries, that may, or may not contain certain package artifacts.

⚠️ There is a limitation for projects with multiple workspaces at the moment: As this plugin hooks into the network requests towards the NPM package registry and the hooking mechanism doesn't provide information for which workspace the request was made, this plugin assumes a package is optional, if it is mentioned in any "optionalDependencies" section of any of the workspace packages. Meaning that even if the package does not exist, installation would not fail for some workspaces, even if they declare the package as a hard dependency in their "dependencies" or "devDependencies" section.

Installation

You can add this plugin to your Yarn 2+ ("Berry") project running the following command:

yarn plugin import https://raw.githubusercontent.com/kristian/yarn-plugin-optional-resolution/v1.2.0/bundles/%40yarnpkg/plugin-optional-resolution.js

Author

Written by Kristian Kraljić.

Found a Bug?

Please file any issues on Github.

License

This package is licensed under the MIT license.