What is a mono repo?

One Repo, many related JS/TS packages, co-located in a git repo.

Why sould i care ?

• Encapsulation tools that JS ecosystem is missing
• One commit can modify many packages, single history of a collection
• Test a family of packages together and before a release
• Dramatically reduced maintanance overhead compared to N Libraries

Problems

• More challenging to manage than a single "monolith" repo
• Sveral new tools we'll need to learn
• new risks you'll need to mitigate
• ...but sometimes it's worth it

Topics

• Yarn workspaces
• TypeScript composite projects
• Build scripts for monorepos
• Lerna
• Api Extractor
• "Pacakge private" and "Project private" interfaces
• Hassle-free "publish to npm" testing
• Versioning strategies
• App and Library Use Cases
• "Wrapper" packages
• Private "dev utility" packages

"C:\Program Files\nodejs\node_modules\typescript\bin\tsc" -b . ``rm -rf /.tsbuildinfo */distin rootyarn add -WD rimraf` `yarn add -WD eslint @typescript-eslint/eslint-plugin @typescript-eslint/parser` `yarn add -DW lerna` `yarn add -DW scripty` `chmod +x scripts/greet` - `chmod -R +x scripts-win/greet` - `chmod -R +x scripts-win` make file executable `ls -all scripts` `yarn add -WD @commitlint/cli @commitlint/config-conventional @commitlint/config-lerna-scopes commitlint husky lerna-changelog` `echo "build(api): change something in api's build" | yarn commitlint` fail because api not is a scope (package) right now `echo "build(types): change something in api's build" | yarn commitlint` `volta install commitlint` `echo "build(api): change something in api's build" | commitlint` fail because api not is a scope (package) right now `rm -r -f .git/hooks/` `cat .git/hooks/commit-msg` `echo "ft(types): more reasonable default types for generics" | commitlint` `echo "feat(types): more reasonable default types for generics" | commitlint`

lerna version lerna version --conventional-commits (to upgrade version)

volta install verdaccio rm -rf ~/.local/share/verdaccio lerna publish --conventional-commits lerna exec 'yarn publish'

lerna add @shlack/utils --scope '@shlack/{ui,data}' lerna add @shlack/types --scope '@shlack/{ui,data}' lerna add @shlack/data --scope @shlack/ui lerna link lerna run dev --scope @shlack/ui lerna run dev --scope @shlack/ui --stream node packages/ui/server/server.js

yarn add -WD @microsoft/api-extractor yarn api-extractor init

lerna exec 'mkdir etc' yarn build lerna api-report

yarn add -WD @microsoft/api-documenter yarn api-docs

lerna link lerna run clean lerna run build --concurrency 2 lerna run test --concurrency 2 --stream

in utils yarn add react date-fns yarn add -D @types/react @types/date-fns

in utils and types yarn add -D @types/jest jest yarn add -D @babel/preset-env @babel/preset-typescript

Install volta

Volata manages global and package specific dependencies.

volta install typescript@3

yarn tsc --version still working tsc --version

ls -all node_modules/.bin

volta pin node yarn

JS/TS Monorepos

Project setup

First, you should ensure you have your ssh keys working with GitHub. You can verify this by running

ssh git@github.com

and getting a response like

Hi jaramillo-carlos! You've successfully authenticated, but GitHub does not provide shell access.
Connection to github.com closed.

Tools

Next, make sure you have installed volta which ensures you have the right version of node and yarn for this project

We also strongly recommend the use of Visual Studio Code as an authoring tool. If you use something else, you're on your own.

Clone

Next, checkout a working copy of this project

git clone git@github.com:jaramillo-carlos/js-ts-monorepos

enter the directory you just created

cd js-ts-monorepos

Install dependencies

yarn is the recommended package manager to use with this project. Please use it instead of npm.

Install dependencies with yarn by running

yarn

Starting the project

Start up the project in development mode by running

yarn dev

Changing any files in the src folder will result in an incremental rebuild, and a refresh of the screen.

By default, the app is served on https://localhost:1234.

Legal

© 2020 LinkedIn, All Rights Reserved

Licensing

The code in this project is licensed as BSD-2-Clause license, and the written content in the ./notes folder is licensed under CC BY-NC-SA 4.0