Yarn Classic's Legacy

Facebook released Yarn 11,798 in October 2016, with engineers from Exponent, Google and Tilde, because npm 3 2,036 was slow and non-deterministic. Yarn introduced a lockfile, a global offline cache and parallel, checksum-verified downloads, ideas every package manager has since copied. npm answered with package-lock.json in npm 5 (May 2017), and Yarn 1.0 (September 2017) added workspaces. Yarn Classic 11,798 has been in maintenance mode since January 2020; its last release, 1.22.22, dates from March 2024. Corepack 3,816 (Corepack) still runs it on demand.

Installing BookNest with Yarn Classic through CorepackShell
mkdir ~/v5-ch1/yarn-classic && cd ~/v5-ch1/yarn-classic && cp ../booknest/package.json .
corepack yarn@1.22.22 install
Output
yarn install v1.22.22
info No lockfile found.
...
(node:358887) [DEP0169] DeprecationWarning: `url.parse()` behavior is not standardized and ...
...
success Saved lockfile.
Done in 4.18s.

The warning comes from Node.js 24 2,131 : Yarn Classic calls an API that current Node.js discourages, which is what "frozen" means in practice. 4 maps everyday commands across npm and both Yarn editions.

Everyday commands in npm, Yarn Classic and Yarn Berry
Task npm 11 Yarn Classic 1.x Yarn Berry 4
Add a dependency npm install pg yarn add pg yarn add pg
Upgrade within ranges npm update yarn upgrade yarn up
Frozen install for CI npm ci yarn --frozen-lockfile yarn --immutable
Install a global tool npm install -g x yarn global add x (removed)