1.0.0 • Public • Published


pkl (pronounced pickle) is a package linker for lerna monorepos. Use it to install packages from your monorepo into your application. This can be useful for trying a package which is in development before you publish it.


pkl can be installed from the npm registry and, as it works across projects, should be installed globally.

Using npm

npm install -g pkl

Using yarn

yarn global add pkl


There's a simple example below of adding a monorepo, listing all added monorepos, using it to install a package from, and then removing the monorepo.

# Add a monorepo (so you can use it during install)
$ pkl add components ./path/to/my/component-library
success: added components
 - Name mapped to /Users/username/projects/path/to/my/component-library

# Show the monorepos you've added
$ pkl ls
success: showing 1 monorepo
 - components → /Users/username/projects/path/to/my/component-library

# Install package "button" into your project from the monorepo
cd ./my-project
$ pkl install components button
✔ button - installed
success: installation complete
 - button (components) → button@1.0.0

# Remove a monorepo (you don't be able to install from it any more)
$ pkl rm components
success: removed components
 - Removed mapping to /Users/username/projects/path/to/my/component-library


To get help on the supported commands, use the --help flag (or run without any flags or commands).

pkl --help

To see which version you have installed, use the --version flag.

pkl --version

Some command use npm as part of their implementation. To use yarn instead, add the --yarn flag. This is only for supported commands; currently install.

pkl install components button --yarn


pkl has four sub-commands; add, rm, ls, install

pkl-add - add a named monorepo


pkl add <monorepo-name>
pkl add <monorepo-name> <folder-path>


This command adds a monorepo name and location, so it shows in the monorepo list (ls) and can be used when running install. If a path to the monorepo folder is not provided, the current working directory (the one the command is run from) will be used instead.

The monorepo name and location are added to the monorepo mapping JSON file, which is stored at ~/.pkl/monorepo-mapping.json and consists of each monorepo name mapping to the corresponding absolute path.

pkl-rm - remove a named monorepo


pkl rm <monorepo-name>


This command removes a monorepo by name, so it no longer shows in the monorepo list (ls) and cannot be used when running install.

The monorepo name entry is removed from the monorepo mapping JSON file, which is stored at ~/.pkl/monorepo-mapping.json.

pkl-ls - list added monorepos and their locations


pkl ls


This command lists all the added monorepo names and locations, which can be used when using the install command.

The monorepo mapping JSON file, stored at ~/.pkl/monorepo-mapping.json, is pretty printed to the console.

pkl-install - install a package from a monorepo


pkl install <monorepo-name> <package-name>
pkl install <monorepo-name> <package-folder-name>
pkl install <monorepo-name> <package-folder-name> [...<package>]


This command installs the named packages from the named monorepo, into the project where the command is run. Packages can be referenced by their name (as listed in the name field of their corresponding package.json file) or by their folder name. Multiple packages can be listed to install more than one in a single command.

Note: For packages without a version, these can only be referenced by their folder name.

Packages to be installed are packed into tar files and moved into a .pkl/ folder within your project. These are then installed -- you may notice your project package.json file referencing file:.pkl/my-package.tgz instead of a version. To prevent committing these files, you should add the .pkl/ directory to your .gitignore.

By default, install will use npm to find lerna, pack packages and install them. If you want to use yarn instead, add the --yarn flag to the end of your command.


This cli tool is written using commander, with each command implemented in its own file under the ./commands folder.

Linting is enforced using eslint, configured with airbnb-base and prettier.

npm run lint

# Run and apply automatic fixes for any issues
npm run lint -- --fix

Unit testing is written and run using jest, and relies heavily on mocking.

npm test

# Run specific test file
npm test -- ./path/to/file.test.js

# Run in watch mode
npm test -- --watch

# Generate coverage report
npm test -- --coverage

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