A monorepo Boilerplate

🔧 Technologies Used

• node 14.x with ECMAScript Modules -> use import/export instead of require and module.exports, having a pretty much modern code! Here's how

• lerna -> main monorepo managing tool. Hoist packages, run commands in parallel through packages etc.

• yarn -> Manage packages. With yarn workspaces working together with lerna, we can have a single lockfile in the project root to manage all packages inside the repo.

• eslint, prettier -> Linting

• jest -> Testing Tool

• github actions -> CI/CD

• codecov -> quality assurance

📋 How to run

You'll need to have installed:

• node >= v14.15.5 (I prefer to use nvm)
• lerna (npm install -g lerna)
• yarn (npm install -g yarn)

Optionally:

• dbaeumer.vscode-eslint
• esbenp.prettier-vscode

💻 Commands

• lerna bootstrap will install all packages dependencies in the root of the monorepo and with a single lockfile.
• lerna run script-name -> it will execute a command in every package that has this command in the scripts tag. It can be lint, test or whatever command you have on the package.
• lerna create ${package-name} packages/lambda --yes will create a package called packageName inside the specified folder. The --yes flag will skip the other package.json init prompts.
• lerna add @config/eslint-config-monorepo --scope=@lambda/example-function -> adds @config/eslint-config-monorepo to @lambda/example-function You can only add one package per time, but you can specify more than one scope with brackets expansions like --scope=@lambda/{example-function,other-function}.

📚 Details

❓ Why do I need a .gitignore inside each package?

I really hate that file being there. I tried to decrease as much as I could the number of configuration files inside each package, but that's a hard task in some cases. The reason is just because the VSCode's ESLint extension tries to find a .gitignore file in each directory that it is running. We are using "mode": "auto" with eslint.workingDirectories to automatically handle each package depending on where the .eslintrc.json file is (see here). So to have codeActionsOnSave and all VSCode's ESLint stuff working, we need a .gitignore in each package. PS: codeActionsOnSave formats your code when you save a file. Very useful since we are using ESLint with Prettier.

❓ Why do I need that NODE_OPTIONS when running jest?

Because we are using ECMAScript Modules and Jest needs that extra configuration to work with it. see here

❓ More questions? :question

Please LMK!