marqetintl / yarn-2-workspaces-monorepo-example

How to set up a basic monorepo with Yarn 2 workspaces

Yarn 2 workspaces monorepo example

This project demonstrates how to set up a monorepo with Yarn 2.

You can either:

• clone the repository or
• set the project up from scratch

1. Cloning the repo

In your work directory, run:

git clone https://github.com/marqetintl/yarn-2-workspaces-monorepo-example.git

Install the required dependencies:

cd yarn-2-workspaces-monorepo-example
yarn

Jump to step 3

2. Setup from scratch

Always refer to the original documentation to get the latest instructions on how to install Yarn.

1. Install Yarn globally, if you haven't:

npm install -g yarn

2. Create project folder:

mkdir yarn-2-workspaces-monorepo-example && cd $_

3. Set Yarn version to latest:

yarn set version berry
yarn set version latest

4. Initialize project:

yarn init -w

If I were to run tree -a -L 1 , the folder tree would look like this:

.
├── .editorconfig
├── .git
├── .gitattributes
├── .gitignore
├── .yarn
├── .yarnrc.yml
├── README.md
├── package.json
├── packages
└── yarn.lock

5. Add two packages myapp-1 and myapp-2 to our monorepo:

cd packages/
mkdir myapp-1 myapp-2

6. Navigate to packages/myapp-2/ and add an index.js file:

cd myapp-2/
yarn init -yp
touch index.js

7. Update packages/myapp-2/index.js:

const defaultName = "Michaël";

module.exports = {
    defaultName,
    logName(name) {
        return console.log(`Hello! I am ${name}`);
    },
};

8. Update packages/myapp-2/package.json:

{
    "name": "@miq/myapp-2",
    "main": "index.js"
}

9. Navigate to packages/myapp-1 and add an index.js file:

cd ../myapp-1/
yarn init -yp
touch index.js

10. Update packages/myapp-1/index.js:

const { defaultName, logName } = require("@miq/myapp-2");

logName(defaultName);
logName("Jean-Michel");

11. Then update packages/myapp-1/package.json:

{
    "name": "@miq/myapp-1",
    "dependencies": {
        "@miq/myapp-2": "workspace:*"
    },
    "scripts": {
        "start": "node ."
    }
}

12. Update the project's package.json:

{
    "name": "@miq/yarn-2-workspaces-monorepo-example",
    "private": true,
    "workspaces": ["packages/*"],
    "scripts": {
        "start:myapp1": "yarn workspace @miq/myapp-1 start"
    }
}

13. From the root folder, run yarn to install the dependencies:

cd ../../
yarn

3. To run the project

yarn start:myapp1

You should see the output:

...

Hello! I am Michaël
Hello! I am Jean-Michel

...

4. Good to know

• List all workspaces:

yarn workspaces list

• Create a new private package and define it as a workspace root with a packages/ directory:

yarn init -w

• Initialize a private package in the local directory:

yarn init -p