Important: This documentation covers Yarn 2. For the 1.x doc, check classic.yarnpkg.com.
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PnPify

Motivation

Plug'n'Play is, by design, compatible with all projects that only make use of the require API - whether it's require, require.resolve, or createRequireFromPath. However, some rare projects prefer to reimplement the Node resolution themselves and as such aren't compatible by default with our environment (unless they integrate their resolvers with the PnP API).

PnPify

PnPify is a tool designed to workaround these compatibility issues. It's not perfect - it brings its own set of caveats and doesn't allow you to leverage all the features that PnP has to offer - but it's often good enough to unblock you until better solutions are implemented.

How it works is simple: when a non-PnP-compliant project tries to access the node_modules directories (for example through readdir or readFile), PnPify intercepts those calls and converts them into calls to the PnP API. Then, based on the result, it simulates the existence of a virtual node_modules folder that the underlying tool will then consume - still unaware that the files are extracted from a virtual filesystem.

Usage

  1. Add PnPify to your dependencies:
yarn add @yarnpkg/pnpify
  1. Use pnpify to run the incompatible tool:
yarn pnpify tsc

Caveat

  • Due to how PnPify emulates the node_modules directory, some problems are to be expected, especially with tools that watch directories inside node_modules.

  • PnPify isn't designed to be a long-term solution; its purpose is purely to help projects during their transition to the stricter Plug'n'Play module resolution scheme. Relying on PnPify doesn't allow you to take full advantage of everything Plug'n'Play has to offer, in particular perfect flattening and boundary checks.