Overview

Yarn is a node package manager for your code that is better than npm or bower. Yarn is created by Facebook in collaboration with Google, Exponent, and Tilde.

Benefits

Faster than npm. It is around 3 to 4 times faster than npm without any cache. It downloads the dependencies in parallel. It is much faster once it is cached. https://www.youtube.com/watch?v=yksxtxqORvY
Deterministic. It will install the same consistent reproducable package dependencies and versions. npm depends on the install order and is non-deterministic (it may download a new minor or patch version) which could break your project.
Works offline
Supports other repos/formats
Backward compatible to npm.
Has Emojies 😎

Setup

Install Yarn

https://yarnpkg.com/en/docs/install OR npm install -g yarn

Configure Proxy
yarn config set proxy http://username:password@yourproxyserver:8080/
yarn config set https-proxy http://username:password@yourproxyserver:8080/

Change Angular CLI to use yarn
ng set = --global packageManager=yarn

Documentation
https://yarnpkg.com/en/docs

Migrating from npm. Run this in your project directory.
yarn