Bazel Example Monorepo

This is my attempt to learn how to use Bazel as the build system for a monorepo.

I'm starting with Javascript and Typescript applications and libraries as I currently work in that ecosystem.

Set up

Install the dependencies first.

yarn

Build instructions

Build everything

yarn build

Build a package

yarn exec bazelisk -- build //path/to/package:target

Run an app

yarn exec bazelisk -- run //path/to/package:target

# examples
yarn exec bazelisk -- run //apps/javascript/no_deps:bin
yarn exec bazelisk -- run //apps/javascript/internal_deps:bin
yarn exec bazelisk -- run //apps/javascript/external_deps:bin
yarn exec bazelisk -- run //apps/typescript/no_deps:bin
yarn exec bazelisk -- run //apps/typescript/internal_deps:bin
yarn exec bazelisk -- run //apps/typescript/external_deps:bin

Packages

Path	Description
//libs/javascript/no_deps	Javascript library with no dependencies
//libs/javascript/external_deps	Javascript library with one external dependency
//libs/javascript/internal_deps	Javascript library with one internal dependency
//libs/typescript/no_deps	Typescript library with no dependencies
//libs/typescript/external_deps	Typescript library with one external dependency
//libs/typescript/internal_deps	Typescript library with one internal Typescript dependency (note: import paths are from workspace root in TS source code)
//apps/javascript/no_deps	Javascript app with no dependencies
//apps/javascript/external_deps	Javascript app with one external dependency
//apps/javascript/internal_deps	Javascript app with one internal dependency
//apps/typescript/no_deps	Typescript app with no dependencies

Notes

The root package.json file is important for bootstrapping all the dependencies used in the repo.

Most of the other package.json files are optional. They are only used if we are building a publishable package using the pkg_npm rule.

Bazel's Typescript support adds the workspace root as an import path so you can refer to local packages easily. See the path in tsconfig.json and the import in libs/typescript/internal_deps/index.ts for an example.

Bundling packages with rollup doesn't seem to work in all cases. I don't know why not.