Contributing to Lerna

First, ensure you have the latest npm.

To get started with the repo:

$ git clone git@github.com:lerna/lerna.git && cd lerna
$ npm i

Code Structure

Currently, the source is split up into a few categories:

Utilities: methods to run git, npm, fs, and more.
Abstractions for packages
Lerna Commands: each command has an initialize and execute function.
- These commands are consumed as yargs subcommands in src/cli.js, which is called from the executable bin/lerna.js.

$ npm test

# watch for changes
$ npm run test:watch

# For a specific file (e.g., in test/Command.js)
$ npm run test:watch -- Command.js

By default, npm test also runs the linter. You can skip this by calling jest directly:

$ npx jest
$ npx jest --watch
# etc

$ npm run integration

# watch for changes
$ npm run test:watch-integration

# For a specific file
$ npm run test:watch-integration -- lerna-publish

$ npm run lint

It's also a good idea to hook up your editor to an eslint plugin.

To fix lint errors from the command line:

$ npm run lint -- --fix

If you want to test out Lerna on local repos:

$ npm link

This will set your global lerna command to the local version.

Note: If the local repo that you are testing in already depends on lerna, you'll need to link your local clone of lerna into the target repo:

# in the target repo
$ npm link lerna

If you would like to check test coverage, run the coverage script, then open coverage/lcov-report/index.html in your favorite browser.

$ npm test -- --coverage

# OS X
$ open coverage/lcov-report/index.html

# Linux
$ xdg-open coverage/lcov-report/index.html