Monorepos with Lerna.js

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What

Why

Who

How

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MONOREPOS

What

What

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Monorepo

A single repository holding the code of multiple projects .

What

What

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Lerna.js

A tool that helps you manage multi-package Monorepos with Git and npm

Created by Babel contributors to help them manage 100+ babel packages.

What

Why

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Why should you monorepo?

  • Manage many apps in a single repo
  • Share libraries across apps
  • Build each app separately
  • Test apps together

  • Teams collaborate more efficiently.

What

Why

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Example use case

  • React Web app A -  website

  • React Web app B -  chrome extension

  • React native Mobile app

  • Shared view components

  • Style guide app

  • Graphical assets library

  • Utilities ( validators / parsers / middleware… )

  • Microservices

What

Why

Why should you lerna?

  • Shared node_modules for multiple apps
  • automatic "npm link"
  • automatic version bumping
  • semantic versioning hints
  • other utilities
  • open source

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What

Who

Who's using Lerna?

https://lerna.js.org/#users

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What

How

How to Lerna?

npm install -g lerna
git init my-mono-repo && cd my-mono-repo
lerna init

Getting Started

https://lerna.js.org/#getting-started

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What

How

How to`s

cli commands, guides & docs

https://github.com/lerna/lerna#readme

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What

How

Workflow

  1. init

  2. bootstrap

  3. commit

  4. publish

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What

How

lerna init

Creates a new Lerna repo or upgrade an existing repo to the current version of Lerna.

lerna init -i

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What

How

Use yarn workspaces

lerna.json

{
  "packages": [
    "packages/*"
  ],
  "version": "independent",
  "npmClient": "yarn",
  "useWorkspaces": true
}
{
  "name": "root",
  "private": true,
  "devDependencies": {
    "lerna": "^3.13.4"
  },
  "workspaces": ["packages/*"]
}

package.json

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What

How

lerna bootstrap

Installing all packages dependencies and linking any cross-dependencies.

lerna bootstrap

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What

How

lerna publish

Creates a new release of the packages that have been updated. Prompts for a new version and updates all the packages on git and npm.

lerna publish

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What

How

lerna import

Transforms an external repository to a monorepo package.

lerna import <path-to-external-repository>

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What

How

lerna run

Runs an npm script in each package that contains that script.

lerna run <npm script> -- [...args]
lerna run build 
lerna run start --scope "foo-*"
lerna run watch --parallel --stream

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What

How

lerna exec

Runs a shell command in each package.

lerna exec -- <shell command>
lerna exec -- ls
lerna exec -- rm rf ./node_modules

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What

How

lerna clean

Remove the node_modules directory from all packages. 

lerna clean [--yes] [--scope] [--ignore]
# Equivalent to:
$ lerna exec -- rm -rf ./node_modules

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